Why are jet fighters scrambled to escort planes in an emergency?

Considered one of two RAF Storm jets that escorted an Air India passenger aircraft to Stansted airport after a reported bomb menace final month. {Photograph}: Luke Hayes Pictures/PAWhen an airliner with a suspected bomb on board (or in another emergency) is escorted to its touchdown website by a jet fighter, what’s the fighter there for?LevelSpirit• Publish your solutions – and new questions – under or e-mail them to nq@theguardian.com