Originally Posted by John26

Yes 43K feet sounds quite normal to me for a UA 777. IIRC they can go a bit higher actually. I can't remember the maximum cruising altitude they taught us in FA Training (maybe it was 49K?), but I remember it was so high that this is the reason 777s carry additional supplemental oxygen onboard in case the initial supply of supplemental oxygen runs out, since it can take longer to decend to a breathable level from such a high altitude.