I prefer airport to airport, especially for anything of even moderate size.
But in many cases 24 hour is what's available, and very good.
but even with 24 hour, if there is a storm, or mechanical error 24 hours may turn into 48, or more.
The biggest killer (or disease cause) in fish is stress.
To me, anything one can do to lessen stress, such as ammonia burn, fluctuating temps, is worth the trouble.
Whenever I received fish thru the US postal service, I would take a vacation day, and arrive at the post office the moment it opens to save hours riding around in a hot, or cold truck, and get them out of bags and into fresh water as soon as possible.