Originally Posted by jackal

What dictates cruising altitude?

I was on a recent string of DL flights (ANC-SLC-ATL-LGA), and it seemed the shorter the flight, the higher we flew--you'd think it would be the reverse! (IIRC, the cruising altitudes for those flights were FL330, 350, and 390, respectively; aircraft were 753, 763, and 752, respectively.)

We did have substantial tailwinds on the first two (~100mph; I'm not sure about the third as there was no AVOD and hence no moving map). I assume that had something to do with it. But FL390 on a short, 700-mile flight? That seems like it would use more fuel to climb than it is worth saving being up that high for such a short time!

I know my experience was on DL, but I hoped our friendly UA pilots (and other pilots frequenting this thread) could speak in general terms about this subject.