4 sentences

1. 这架飞机的航线偏离了预定轨道。

   zhè jià fēi​jī de háng​xiàn piān​lí le yù​dìng guǐ​dào.

   The aircraft's flight path deviated from the planned course.

   Source: Dong Chinese Dictionary

2. 航空公司开通了飞往伦敦的新航线。

   háng​kōng gōng​sī kāi​tōng le fēi​wǎng Lún​dūn de xīn háng​xiàn.

   The airline has opened a new route to London.

   Source: Dong Chinese Dictionary

3. 航空公司最近开辟了几条新的国际航线。

   háng​kōng gōng​sī zuì​jìn kāi​pì le jǐ tiáo xīn de guó​jì háng​xiàn.

   The airline has recently opened several new international routes.

   Source: Dong Chinese Dictionary

4. 这条航线上，走下水的船比走上水的船快得多。

   zhè tiáo háng​xiàn shàng, zǒu xià​shuǐ de chuán bǐ zǒu shàng​shuǐ de chuán kuài de duō.

   On this route, ships going downstream are much faster than those going upstream.

   Source: Dong Chinese Dictionary