If a commercial airplane were to hit a standard latex or Mylar balloon, the most likely outcome is that absolutely nothing significant would happen. Commercial jets are built to withstand much more intense impacts, such as bird strikes from heavy geese. If a balloon hits the fuselage or a wing, it would simply pop or bounce off, perhaps leaving a small, negligible smudge of residue. If the balloon were ingested by a jet engine, the high-speed compressor blades would instantly shred the thin plastic or rubber into tiny fragments, which would then be vaporized in the combustion chamber and expelled out the back as gas. The only potential—though still remote—risk would be if the balloon's string or any small metal weights attached to it were to get tangled in external sensors like a Pitot tube (which measures airspeed) or an engine temperature probe, which could lead to minor instrument errors. However, pilots are trained to handle such sensor malfunctions. While hitting a single party balloon is not a safety threat, authorities like the FAA strongly discourage releasing large clusters of balloons near airports, as they can be mistaken for more dangerous objects like small drones or "unidentified aerial phenomena" by pilots and radar systems.