Our taste buds and sense of smell are altered in a plane. In this low-humidity environment your nasal passages dry up, which causes tastebuds to become less sensitive to salty and sweet flavours.

Beer tastes different on a plane due to a combination of low humidity, cabin pressure, and background noise. At 35,000 feet, the humidity in an airplane cabin is often lower than 20%—drier than some deserts. This dry air dehydrates your nasal passages, which are responsible for 80% of what we perceive as "flavor" through our sense of smell. Furthermore, the pressurized environment affects how carbonation behaves; the bubbles in beer may feel "thinner" or dissipate faster, which changes the mouthfeel. Studies have also shown that our sensitivity to sweetness and saltiness drops by up to 30% in a pressurized cabin, while our perception of bitterness (the hops in beer) remains relatively stable. This makes a standard lager taste more bitter or "metallic" than it would on the ground. Interestingly, "white noise" from the engines has also been shown to suppress our ability to taste sweetness while enhancing savory flavors, which is why many people find themselves craving a savory Tomato Juice or a Bloody Mary mid-flight rather than their usual choice of a light, sweet beer.