noun
involuntary upgrade; operational upgrade; free upgrade on overbooked flight
Abbreviation of インボランタリーアップグレード. Used in travel and airline contexts for a free upgrade to business or first class when economy is overbooked.
See also: インボランタリーアップグレード
今回のフライトでインボラをもらって、初めてビジネスクラスに乗れた。
I got an involuntary upgrade on this flight and was able to fly business class for the first time.