Narrative:

I was a passenger on a commercial flight. The flight was delayed about 3 hours from its original departure time. While at cruising altitude deep into the flight; I was looking out the window and saw another jet; maybe smaller; pass by on the starboard side. I estimate that the other plane was at almost exactly the same altitude. My gut feeling is that it was about 200 yards away; though it's possible is was more. I also noted that our aircraft made no evident course adjustment before or after what I witnessed.I have no professional or private aviation experience. It's my understanding that a 'near miss' must be generally within 1000 feet. But I don't know if that's a real guideline. It is my belief that this encounter at cruising altitude was at virtually the same vertical distance and under 1000 feet horizontally. I was going to ask the pilot when deplaning if possible; but the exit was mid-ship; so I didn't get the opportunity. Heck; maybe this happens all the time. It just seemed really close. I've seen other aircraft pass at cruising altitude before; but never this close.

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Original NASA ASRS Text

Title: A B757 passenger reported seeing another aircraft while at cruise. The aircraft appeared close; but neither aircraft crew took no evasive action. The passenger sensed the aircraft was about 200 yards away.

Narrative: I was a passenger on a commercial flight. The flight was delayed about 3 hours from its original departure time. While at cruising altitude deep into the flight; I was looking out the window and saw another jet; maybe smaller; pass by on the starboard side. I estimate that the other plane was at almost exactly the same altitude. My gut feeling is that it was about 200 yards away; though it's possible is was more. I also noted that our aircraft made no evident course adjustment before or after what I witnessed.I have no professional or private aviation experience. It's my understanding that a 'near miss' must be generally within 1000 feet. But I don't know if that's a real guideline. It is my belief that this encounter at cruising altitude was at virtually the same vertical distance and under 1000 feet horizontally. I was going to ask the pilot when deplaning if possible; but the exit was mid-ship; so I didn't get the opportunity. Heck; maybe this happens all the time. It just seemed really close. I've seen other aircraft pass at cruising altitude before; but never this close.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.