Both light exposure and feeding time are well-known regulators of the circadian clock. Oxygen appears to function as a resetting cue for circadian clocks. Interestingly, the majority of modern commuter airplanes have a cabin oxygen pressure corresponds to ∼16% O2, which may actually aid in jet lag recovery.
Maybe having a few bitter almonds after the flight will do it…
Note: bitter almonds contain amygdalin which is split into the aromatic benzaldehyde and the highly toxic hydrocyanic acid blocking cellular respiration. There are fringe theories about amygdalin being an anti-cancer agent, but they are not supported by evidence. Anyway, ingesting low dose will result in mild, temporar hypoxia, which may have beneficial effects. The lethal dose is roughly 1 almond per kg of body weight, so make sure never to exceed 1/10th of that dose.
I think bitter almonds are actually illegal in the US but they are freely available in health food stores in many European countries for traditional bakery (as hydrocyanic acid is highly heat labile). However, many people believe in their health-promoting effects and regularly eat small quantities of them raw. That may actually be true, but not because of the alledged anti-cancer effect but because of the hormetic effects of mild hypoxia.
Another interesting aspect of dietary cyanides is the fact that they serve as a substrate for thiocyanate, an endogenous compound concentrated in saliva, sweat and tears, where it plays an important immunologic role in the defense against pathogens, its concentration greatly increasing during infectous challenge. Moreover, thiocyanate may excert some beneficial effects similar to the closely related isothiocyanates found in cruciferous vegetables. Thus amygdalin, as well as other cyanide-releasing dietary compounds, may in fact have cancer-protective properties - just not the direct cytostatic effect some people claim, which has actually been falsified in human trials.