One of the longest nonstop flights in terms of distance flown is the Delhi-SFO route. AI's Boeing 777 from Delhi landed safely in SFO & a hole was discovered upon arrival. The airline is now investigating how & where did the area below door gets damaged. Luckily, there was no cabin de-pressurization on the Delhi-SFO route & cabin pressure was maintained throughout. But some claim there was a hissing sound coming from the door.