How big, to the naked eye, should a passenger aircraft be when it is at 3000ft and I am stood outside looking up at it?

[mrsouthg]

Purely a maths question this, I'm hoping someone can help?

[Mamyalynne]

Do you know the size of the aircraft when it is on the ground?? This is crucial.

[Buenchico]

The wingspan of a Boeing 737-800 is 35.8m.

3000 feet = 914.4m.

That means that the aircraft subtends an angle of approximately 2¼ degrees at your eye. Assuming that you're sitting with your eyes 60cm away from your monitor, that's the same angle as the image of an aircraft on your screen which is about 4.7cm wide.

Chris

[Answerprancer]

For some real life info - try this:
http://www.flightradar24.com/