When JetBlue Airways entered the Twin Citie­s market last May with one-way fares to Boston's Logan International as low as $62, it led to something of a Boston fare massacre. Spirit, Sun Country and even Delta airlines jumped in, offering their own sub-$100 seats.

The competition was good for budget travelers — including me.

I enjoy flying. Just give me a window seat, and I'm easy to please. But I am also cheap, think the destination is more important than the flight and refuse to be loyal to any one airline. I believe air travel should be accessible to everyone. So I leapt at the chance to sample the low airfares last summer.

In this discount dogfight, I first flew to Boston on Spirit, the cut-rate pioneer, for a rock-bottom $51.20. I came home on Minnesota-based Sun Country for a respectable $62.20. A month later, I flew to Boston on JetBlue, again for $62.20.

I wanted to find out how much I would sacrifice to pay as little as possible to fly — and whether the loss of comfort and convenience would be worth the savings. Other travelers seem to be exploring the same questions, because budget airlines are growing fast.

Last week, Sun Country announced 19 new routes, including eight from Minneapolis-St. Paul, and said it expects to carry 40 percent more passengers in 2019. And while Spirit routinely ranks last in customer satisfaction for its nickel-and-dime approach to fees and its miserly amenities, the airline increased its passengers by 19 percent to about 25 million in 2018, expanding from 60 to 69 cities.

Buoyed by low fuel prices this decade, ultra-low-cost carriers (ULCCs) such as Spirit and Frontier have changed the face of flying for budget-conscious leisure travelers like me. Need proof? Since 2017, legacy airlines Delta, American and United have all responded by extending their own no-frills fare options (such as Delta's Basic Economy). Meanwhile, Sun Country has adopted some features of the ULCC model, with a twist.

It was Spirit that first started charging fees for all checked bags in 2007, and carry-on bags in 2010. Today, almost all major carriers charge at least $30 for a checked bag, but Spirit and Sun Country take it up a notch with carry-on fees. The latter fee is probably the most obnoxious, because nearly everyone has to pack for a trip. To avoid paying for my change of clothes in Boston, I chose a small, 20-liter backpack as my free personal item and set off.

Spirit for $51.20

A month before my trip, I rediscover that booking on Spirit.com takes a few extra minutes, because the airline runs a lot of side hustle. I select my $51 one-way "bare fare."

I'm immediately offered a "Thrills Combo," a bundle of goodies that includes a checked bag, a carry-on, seat choice, "shortcut boarding," a free flight change and double the frequent-flier miles, all for the low-low price of $61.99 (or $48.99 with a $59.95 Spirit membership). But I don't want to pay for anything extra, so I pass.

In checkout, Spirit gives me another chance to purchase a carry-on bag for $37 or checked bags for $32, with a pop-up warning "If you change your mind, they'll only be more expensive at the airport." They're really trying here. Pass!

Next up is seat fees. Spirit wants a minimum of $5 to preselect my own seat at the back of the plane, up to $43 for a 25-percent-wider "Big Front Seat" in the first two rows. I reluctantly pass on that, too.

I get two more pitches for the exciting Thrills Combo, plus a few other promotions. Pass, pass, pass. I'm informed that I can check in online for free, or prepay $10 to check in with an airport agent. Talk about nickel-and-diming. Finally I get my itemized bill of $51.20, helpfully noting the "Government's Cut" of $15.39 (thanks, Spirit, I did not know what taxes were).

I check in online the evening before my flight and receive a boarding pass with seat 24C — an aisle. When I arrive at MSP's Terminal 1 at 5:30 a.m. (one drawback of cheap flights: often ungodly hours), the Spirit agents are still trying to sell Big Front Seats, which have risen to $48. Boarding the Airbus A319, I see a "Fit Fleet" sign claiming that Spirit has the youngest fleet among U.S. airlines. Spirit's aggressive penny-pinching has at least one advantage: more fuel-efficient aircraft. That's nice to know.

Before I ever flew Spirit, I envisioned a rundown cabin full of crying babies and influenza. But this A319 does have that new-plane smell, the aisle is wide, and those $48 Big Front Seats now look pretty appealing, like a poor man's first class.

Further back, Spirit's legendary sardine-can layout is on display, with 28 inches of seat pitch (the distance between rows) that is the least among U.S. airlines. The "deluxe leather" seats are in reality about one or two inches thick, and they don't recline, an unwelcome realization at 7:11 a.m.

My maxed-out personal item fits snugly beneath the seat in front of me, but then there's little space left for my feet. My own seat is 17 inches wide. And the tray table — a 5- by 10-inch metal square — doesn't look like it could secure a drink.

Not that there's going to be a drink. Spirit charges for drinks, snacks and even water. I don't have a menu anyway. Not surprisingly, after takeoff, the beverage cart moves up and down the aisle in about three minutes, making few stops for sales.

Other absent amenities: no in-flight magazine, no earbuds, no pillow, no Wi-Fi, definitely no entertainment. I've brought a neck pillow, but I don't sleep well without a reclining window seat. So instead I'm just tired, uncomfortable and bored for three hours, punctuated by a sales pitch for the Spirit Mastercard — with a paltry 21,000-mile sign up bonus.

Spirit's loyalty program, too, is pretty stingy: I earn 562 miles for the trip (half the miles actually flown), which is about one-fifth of the amount needed for the smallest possible, restriction-laden reward. Worse, the miles may expire after only three months of inactivity.

The flight arrives a modest 16 minutes late (little-known fact: Spirit became one of the top U.S. airlines in on-time performance in 2018). The overhead bins are not that crowded, thanks to that higher carry-on fee, so it takes nine minutes from docking for me to walk off the plane. It's my first time in Boston, and soon I've forgotten all about Spirit Airlines. And I've saved enough on my flight that I can splurge on a hotel, a nice dinner, a Red Sox ticket (they won, 8-7) and a Boston Harbor islands cruise.

Sun Country for $62.20

Under new ownership, Sun Country's transition to a budget airline has been turbulent, with a high-profile incident last year in which passengers were stranded in Mexico. Can the hometown team find redemption?

Booking my return flight on Sun Country's site is straightforward, except for the ultra-low-cost dance around baggage fees and seat assignments. I decline both and buy the bare $62 flight back to Minneapolis.

Before I take the Boston water taxi to the airport, I start to check in on my phone and see that several seats are open in the back for "only" $4 to $9. That's a relatively small price to guarantee a window, but I refuse to play the game. At the airport, I check in for free with a human agent (there's no line), who hands me my boarding pass with seat 26F — a window. Score! I'm in Zone 5, among the last to board because I don't have a carry-on.

Entering Sun Country's Boeing 737, I'm immediately struck by one difference from Spirit: sumptuous headrests on every single seat. After Spirit's deck of playing cards for seats, this feels luxe.

The seats have 31 inches of pitch (average, but 3 more than Spirit), and are again about 17 inches wide — and they recline. My personal item easily fits under the seat, this time allowing enough room for my feet. The carry-on bins are less than a third full. The airline's Connections travel magazine, highlighting some of SC's warmer destinations, is in my pouch.

During the flight, I can even order a complimentary ginger ale, and not only that, the flight attendant refills my empty cup with water! It's the little things. The new-era Sun Country still offers Minnesota-favorite Surly Furious IPA for $8 — classy.

The flight pulls into MSP's Terminal 2 at 11:37 p.m., a half-hour late. The pilot blames the "air-traffic control delay" on earlier weather; evening flights are more likely than morning flights to be delayed. A JetBlue flight from Boston to Minneapolis, scheduled at the same time, comes in 45 minutes later.

Since my trip, Sun Country has renovated its cabins with USB outlets, free streaming entertainment to your own device, and three tiers of legroom to pay for — 30, 32 and 34 inches. But now, if you don't prepay for a seat, you won't be able to check in online. Sun Country also changed its rewards program with members earning two points per dollar spent — I would now get a minuscule 124 points from my flight, for a redemption value of $1.24.

Both Sun Country's and Spirit's programs are a little better with a branded credit card, but let's be real, you don't fly these airlines for the rewards.

JetBlue for $62.20

Both Spirit and Sun Country can take a page from my experience flying JetBlue back to Boston one month later, on my way to a Portugal vacation. While it's the first time I actually witness a passenger having her oversized carry-on denied at the gate, I enter the Airbus A320 and gasp.

The plush leather blue-gray seats all have 32 inches of pitch — I haven't seen this much space in coach since I was a kid. My built-in entertainment screen features a few DirecTV channels and even some Sirius­XM music stations. Service includes a complimentary ginger ale and genuinely tasty Terra Chips, among other options. Best of all: There's free Wi-Fi by signing up to the True Blue loyalty program — and it works. I can even log into my Amazon Prime account and start watching video. This three-hour flight goes way too fast.

Here's the bad news: Boston is MSP's only destination for the East-centric JetBlue, so until further notice, the carrier won't play a big role for Minnesotans.

Still, low-cost airlines are the new reality, especially for casual travelers looking for the occasional getaway. If you take the time to do the math, you can often save a lot of money with Spirit, Sun Country or another budget carrier, or you might find a higher level of service (and free carry-on bags) for not much more with the likes of JetBlue or a Delta Basic Economy fare.

But for only $11 more than Spirit, along the same 1,124-mile stretch of sky, both Sun Country and JetBlue provided more comfort and amenities — proving that the budget flying experience doesn't necessarily have to feel cheap.

Simon Peter Groebner • 612-673-7012 • Instagram: @simonpeter6