飞美国的应该可以。
The US Department of Transportation (DoT) consumer rule “Enhancing Airline Passenger Protections” (14 CFR 259.5(b)(4), 76 Fed. Reg. 23110, 23166, Apr. 25, 2011) requires that U.S. and foreign air carriers either hold a reservation at the quoted fare for 24 hours without payment or allow a reservation to be cancelled within 24 hours without penalty, for all reservations made seven days or more prior to the flight’s scheduled departure time