Your reaction worked—but it crossed a line.
Yes, you solved the problem instantly: the behavior stopped, and you made a lasting impression. But putting gum in someone’s hair can be considered property damage or even assault. That move risked a serious in-flight escalation, especially under strict airline safety policies.

There’s a difference between setting boundaries and revenge.
Your frustration was valid—being ignored repeatedly in a tight, shared space is maddening. But turning to physical retaliation shifts the situation from boundary enforcement to potential harm. The moment someone’s body or belongings are altered, the line from assertiveness to aggression gets blurred.

Better options next time: flag a flight attendant after your second warning, or stand in the aisle as a silent cue. Even taking a discreet photo of the hair on your tray (no faces) gives you documentation without conflict. Cabin crew are trained to handle these issues before they spiral.

Final verdict: You had every right to defend your space, but your method carried high personal risk. The gum move was emotionally satisfying—but legally and ethically risky. Next time, let crew intervene. You’ll keep your cool, your seat, and your legal safety—all intact.