Since the latest change to wait time calculation at airports, these appear to be far different to what I imagine was intended. It seems that non-air routes from and between airports are subject to the minimum wait time of 45 minutes, while not all air routes are affected in the same way.
(https://media.discordapp.net/attachments/737992455361658891/1151870955052875887/image.png?width=353&height=623)
In this example, wait times to stations on local bus and rail routes (e.g. Hurlham 43, Hurlham 61, etc) are 45 minutes, while wait times to Noranavan Horrible Dock served by air routes are 9:54 minutes.