Originally Posted by
Deltican
This may need to be moved.. Yesterday afternoon flying on AA from ATL / DFW, we were about 30 minutes out.. I was in the window seat and the gent beside me was talking looking out the window.. he stopped talking and told me to look. There was a SouthWest airlines jet flying crossing under us. Best that I could tell.. our plane had not made any corrections or adjustments.. but we could see the people in the windows. I wanted to wave..

I am sure this has happened before.. just never seen it this close. I was trying to google how close planes can get to one another... anyone know? Thanks
Normally, 1,000 ft. is the required vertical separation. If the pilots of one or both aircraft see the other aircraft, visual separation can be applied which allows the pilots (at their discretion) to fly closer to one another. Due to the sensitivity of the TCAS equipment, it's rare that air carrier pilots will ever fly closer than 500 ft. vertically.