A Southwest Airlines aircraft taxis as an American Airlines aircraft lands at Reagan National Airport in Arlington, Virginia, U.S., January 24, 2022.Joshua Roberts | ReutersU.S. airline bookings dropped 17% last month from March, according to a report from Adobe published Thursday, one of the first signs of cooling demand for air travel as ticket prices surpass pre-pandemic levels.Consumers spent $7.8 billion on domestic tickets in April, down 13% from the previous month, according to the report. Air travel has been resilient in recent months despite the highest inflation since the early 1980s. Prices on everything from gasoline to groceries to travel have shot up. The new data suggests consumers are starting to back off buying tickets.Despite the slowdown, demand for domestic U.S. plane tickets remains above 2019 levels. In April, online spending on tickets was up 23% over the same month of 2019 while bookings were up 5%. Prices were up 27% from 2019 and 8% higher than in March, Adobe said.