Understand flights and elevation versus water-resistance ratings — not just underwater use.
A 100m or 200m sports watch is generally fine for normal passenger flights. Water-resistance meters are not an altitude rating; the real topic is cabin pressure change and seal condition.
Water-resistance ratings measure underwater pressure performance. Flights and mountains are about **air pressure change**, seal condition and sometimes temporary crystal behavior — not “100m equals X altitude.”
Is it safe to wear a dive watch on a plane? Usually yes for normal passenger flights.
Can airplane pressure affect a watch crystal? Temporary effects are discussed by owners; healthy sealed watches are typically fine.
Does 100m mean safe at high altitude? No — it is not an altitude rating.
Should I unscrew the crown before a flight? Follow brand guidance; secured crown is the normal daily state for screw-down watches.