Why do your feet swell during aeroplane flights? It’s not sudden-onset elephantiasis (probably).

Instead, it’s due to blood pooling in your veins. (As blood tends to do when stationary, thanks to gravity.)

Yes, gravity strikes again!

References

1. Sheps, S. (2016). Foot swelling during air travel: A concern?. Retrieved from https://www.mayoclinic.org/foot-swelling/expert-answers/faq-20057828