red-eye flight 红眼航班

A red-eye flight is any flight departing late at night and arriving early the next morning. The term red-eye, common in North America, derives from the fatigue symptom of having red eyes, which can be caused or aggravated by late-night travel. Inside the US these flights almost exclusively travel from the West to the East. These flights are very low cost since significantly less people acquire them due to the inconvenience of touring so late at evening.

红眼航班是深夜出发、第二天凌晨抵达的航班，在北美很常见。由于深夜飞行导致两眼发红的疲态，所以被称作红眼。在美国国内，红眼航班基本都是从美西飞到美东。这种航班票价很便宜，因为深夜旅行很不方便，所以很少有人买。

For example:

A red-eye flight is much more economical.

红眼航班更经济实惠点。