Better allow crypto payments in BTC or ETH in order people can pay whatever they want. It is my opinion.
This. Why developing a whole new cryptocurrency when you can developed a secure, easy to use software for airlines and hotels to use without too much cost?.
Bitcoin and Ethereum are really young still in comparison to the regular monetary system so it is just a matter of time before it happens. It depends highly on the amount of acceptance of them so the more costumers that asks them for that payment method, the more they will consider creating and/or activating it.
It can also be extended towards practically anything and it's definitely needed.