The reasons for that are unclear, especially since the birds make several stops during their return flights to Sweden in the spring.

它们这样做的原因尚不明确，特别是它们在春天返回瑞典的途中会休息好几次，更是让大家摸不着头脑。

youdao

Xiamen Airlines does not require reconfirmation of existing reservations for onward or return flights of Xiamen Airlines.

对于已定妥厦航续程或回程航班座位，厦航不再要求进行再确认。

youdao

The CityFlyer service from Edinburgh to London has been scaled back from eight to six return flights a day.

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Return flights will depart from Rio de Janeiro on Mondays, Thursdays and Saturdays.

WSJ: Weekend Rejuvenation, Courtesy of Marriott

Working hours are capped so that return flights sometimes require two separate crews, and in some cases the company must train its own pilots rather than hire cheaper outsiders.

ECONOMIST: Mexican airlines