中翻英：如果你愿意乘夜晚的航班，你就可以买到一张便宜得多的机票。（willing）

You can get a ticket with much lower price if you are willing to take the night flight.

航班应该用“flight”，翻译成airplane是不地道的，另外airline表航线之意，也是错的。

You will get a much cheaper ticket if you are willing to take the night airline.

YOU CAN BUY A CHEAPER TICKET IF YOU ARE WILLING TO TAKE THE FLIGHT
AT NIGHT

You can buy a ticket at a much cheaper price if you are willing to emplane at night