寄托天下

Not really, nowadays there are a lot of low cost carrier, that have a very low flight fare. This cheap fare can fight wif the train. And also not only Air China fly to international route, there are China Southern, Eastern, etc.
BTW,The largest part of passengers in China buy very cheap non-sleeping tickets, even for long-distance ride, like from Harbin to Guangzhou. This fare is unbeatable.