Originally Posted by
Bend alot
Aircraft do not operate at sea level.
There are plenty of airports adjacent the ocean whose runway surface, in the context of engine performance, is not meaningfully higher than sea level.
Would you say that an airplane in the middle of it's take-off run at such an airport is operating or not operating?
That said, do you seriously not realize that sea-level ISA standard day is a common reference for aircraft performance, and more specifically engine power output? Take a look the Type Certificate Data Sheet for almost any piston engine. The Rated power is referenced to sea level.
Besides, what on earth is your point? The point LB was making with his rhetorical question is the same whether he'd used sea level, 1,000 ft, or 10,000 ft.