Joining or taking part on the spur of the moment without prior registration; a last-minute entrant or impromptu participant.
街頭ライブで隣のバンドのメンバーが飛び入りで演奏した。
At the street live show, a member of the next band jumped in and played impromptu.
今日の会議には飛び入りで参加した人が数名いた。
A few people joined today's meeting as last-minute attendees.
テレビ番組では観客の飛び入りコーナーが人気だ。
On TV programs, the audience's impromptu participation segments are popular.
A rare/specialized usage referring to speckling or small spots on flower petals (a flecked pattern).
この菊は花弁に淡い飛び入りがあり、趣がある。
This chrysanthemum has faint speckling on its petals, giving it character.