往返机票的英文可以用round trip air ticket 或者 return ticket。
一、短语
往返机票的订单 Reservation on return ticket
双往返机票 back-to-back
备好往返机票 Air tickets
二、例句
1、往返机票是多少钱？
How much is the return ticket?
2、届时，费米项目的科学家们就不只是开香槟庆祝了；他们完全可以开始预订到斯德哥尔摩的往返机票。
At that time, Fermi scientists may do more than just uncork the champagne; they can startreserving themselves a round-trip ticket to Stockholm.
3、携带公司证明文件的乘客可以换取折扣或者免费（虽然很罕见）的往返机票。
Passengers carry documents on behalf of a company in return for a discounted, or free (thoughrarely), round trip.
哈鲁咕噜
