In this articleAALALKUALDALFollow your favorite stocksCREATE FREE ACCOUNTSick of the heat, crowds and high prices, more U.S. travelers are discovering the offseason of international travel — and airlines and hotels are fighting for a windfall.Flights to once-seasonal European vacation destinations now start when there’s still snow on the ground in the U.S. and wrap up when leaves are falling off the trees, if they end at all, instead of following traditional late-spring to late-summer travel seasons.For example, American Airlines’ flight to Edinburgh, Scotland, from New York began in March. United Airlines’ nonstop route to Palermo, Sicily from Newark, New Jersey, will end in December and Delta Air Lines’ service to Rome from Minneapolis, Minnesota, will run into January, months later than they have in past years.With this year’s surge in jet fuel expected to take a $100 billion bite out of airline profits this year, according to the International Air Transport Association, it’s crucial for the industry to maximize on travel trends that attract high-spending customers.Investors are upbeat that airlines can take the fuel hit from earlier this year after they trimmed unprofitable or less profitable flights and airline executives have said strong demand has helped them pass some — but not all of those expenses along.Shares of Delta and United, the two most profitable U.S. airlines, each hit records in recent weeks, and American’s shares touched an 18-month high. Airlines start reporting second-quarter results and providing third-quarter updates this month, with Delta kicking the season off on Friday.A couple cools off in the Trocadero Fountain with the Eiffel Tower in the background during a heat wave in Paris on June 26, 2026.Dimitar Dilkoff | Afp | Getty Images’Creep of the seasons’Industry executives told CNBC that international vacation seasons used to be more defined. The new trends are forcing them to rip up decades-old playbooks.”It used to be so much lumpier. There used to be more: good season, bad season,” Delta President Peter Carter said in an interview. “There are so many places you can go in Europe year-round and still have an amazing experience, and that’s why we’re seeing such good demand into Europe.”That demand is redefining when airlines’ moneymaker months are.”We’ve seen this massive, what I would call, the creep of the seasons — the shoulder season is blending into the full season,” Patrick Quayle, United Airlines’ senior vice president who designs the carrier’s network, said in an interview last month. Shoulder season refers to the period between a destination’s peak tourist season and its offseason.Airlines are trying to extend the season as much as possible to grow profits.International flights to Europe generally carry more premium seats like lie-flat pods than smaller jets that are used for domestic travel — and airlines are planning to expand those options further. Business-class fares on some of those routes can cost $10,000 for a round-trip instead of less than half that on a domestic route.A dog is standing with its owners in a long line at Terminal 1 of Frankfurt Airport in Germany.Andreas Arnold | Picture Alliance | Getty ImagesAirfare overall is up this year compared with last as airlines try to pass along as much of their rising costs to customers as possible, but there are signs that prices are moderating, particularly as the industry braces for the peak summer travel period in July to pass.For example, flights between the U.S. and Athens, Greece, on June 22 were going for $988 round-trip, up from $810 last year but down from $1,350 two months earlier, according to flight-tracking site Kayak.The increase in shoulder season and off-peak travel is forcing Delta to rethink its maintenance and crew schedules, said Jeff Arinder, Delta vice president of international network planning.”We would never give airplanes to the maintenance hangers, if we could avoid it, in the summertime … because that’s when we made all the money,” he told CNBC. “We are now doing more maintenance in the summertime because we want to save those planes for the fall.”He said Delta is trying to “really flatten out our seasonality as much as possible.”Why travel times are changingPeople try to cool down by standing in front of a nebuliser placed on a Civil Protection pick-up truck spraying cool water during a heatwave, in Rome near the Colosseum on June 26, 2026.Andreas Solaro | Afp | Getty ImagesThe latest challenge to usual summer European travel was the most recent, deadly heat wave. In late June, locals and tourists alike faced dangerous record temperatures throughout Europe, where air conditioning isn’t widespread. Misting stations were set up from Warsaw, Poland, to Rome. The Paris LGBTQ+ Pride march was postponed, among other events, and public alcohol consumption was briefly banned in the city.Residents of many European cities, like Barcelona, Spain, and Venice, Italy have also been raising concerns about overcrowding during peak summer months and beyond. Countries throughout Europe have been bringing in record numbers of visitors. But it’s not just an aversion to heat and crowds that’s leading to changing travel patterns. For younger generations, more flexible work policies are helping some consumers, even those with children, take trips outside of late spring and summer. Baby Boomers, meanwhile, are armed with piles of cash and plenty of time, giving them more flexibility for travel. “Delta’s target demographic tends to be a little bit older and a little bit wealthier,” Arinder said.Setting sights on SicilyUnited is pushing the limits of the offseason trend. It’s extended its nonstop flight from Newark, New Jersey, to Palermo, Sicily, through Dec. 16, rather than ending it in September, with Boeing 767s.Sicily has long been marketed as a summertime destination.Daytime highs can regularly reach 90 degrees Fahrenheit along the coast with little, if any, rain in July. In December, however, the highs sometimes barely touch 60 degrees on the Italian island and rain is …