[nudephil (OP)]

Here's a question sent in by Alex:

Suppose a fly were to follow a person entering the world's tallest building, and continued following them into an elevator destined for the observatory deck (the highest point). Would the fly's flight be affected by the extreme height?

Any ideas?

[Kryptid]

The air density at the top of a building wouldn't differ much from that at sea level, so I wouldn't expect it to make much difference.

[alancalverd]

3000 ft is not very high. If it were, the flies at the top of Snowdon would behave erratically and there would be no flies on Everest. Flies are perfectly happy to share my lunch in an unpressurised cockpit at 10,000 ft and show no signs of distress or impaired airmanship. Swarms of flying insects like to migrate around 12 - 20,000 ft where the winds are strong and consistent: their operational limit is more likely determined by temperature than air density.