Ythrian Travel Problems

Paradoxically, the Ythrians' psychological need to be surrounded by the open air limits their travel options. Unable to fly between continents yet claustrophobic in enclosed vehicles, they prefer aircars that have transparent cabins although such vehicles are necessarily frail and slow.

Technic civilization teaches Ythrians to become space travelers but:

an Ythrian cannot remain sane while enclosed in a spacesuit so they die if a spaceship hull is breached;

they always need enough room to spread their wings so their interplanetary craft must be larger than those designed for human use;

in an interstellar craft, they need both a large port with a view of space and a flying hold, two unnecessary extravagances in a human ship.

Eventually I might have summarized all the information that Poul Anderson imparts about Ythrians.