Pilots frequently encounter lost IFR flight plans due to delays or errors, necessitating re-filing or confirmation with ATC or Flight Service. To ensure an IFR flight plan is active, pilots should use ...

A "pop-up" is an on-the-spot IFR clearance from Air Traffic Control (ATC), often granted without a pre-filed flight plan or briefing, serving as a vital safety option to avoid hazardous scud running.