This summer is shaping up to be sizzling hot for the short-term rental industry, with more travelers booking trips in advance than ever before.

Booked vacation rental demand is already up 10% from last year's highs, according to a new report from AirDNA. More than 21 million nights were booked for future travel in March, more than any month on record.

In addition to future bookings, demand has already been up this spring, with 15.8% more short-term rental stays in March than in the same month last year.

"This spring, we are seeing strong signals that the short-term rental industry will defy #airbnbust speculations," Jamie Lane, vice president of research at AirDNA, said in a press release.

Large U.S. cities are seeing the highest demand in bookings, with Southern states leading the charge. Orlando and Panama City in Florida and Myrtle Beach, South Carolina, saw the most nights booked at 580,000, 463,000 and 422,000 rooms booked, respectively.

Other vacation spots seeing high demand growth include Mobile, Alabama, Cape Cod, Massachusetts, and Gatlinburg, Tennessee.

Although short-term vacation bookings are thriving in these larger urban areas, full-service hotels aren't seeing the same type of demand, especially for transient corporate activity.

Upscale hotel occupancy in urban areas during the first quarter was 86% of the quarterly average between 2015 and 2019, according to CoStar. Researchers say the rise in office vacancy could be correlated with the low hotel demand, as businesses are less likely to have employees travel to meet people in their offices.