Some nice shots squad and welcome to the forum. Did you take these shots with a small hand held camera held up to a telescope? I think I saw these on another forum 
Thanks EGAA, Casper & Dave,
Yes Dave thats correct, it's a simple as that, with some provisions attached.
Obviously the spotting-scope/eyepiece has to be of good quality, prefrebly HD glass with larger (80mm) Objective lens.
The sun is the other big factor, how it reflects of the plane etc., your distance and position (sun behind you) from the plane and of course camera shake,
usually caused by a low shutter speed or maybe cheap tripod thats motion would not be very fluid.
The beauty of all this is being a Birder I had all the equipment already, but having a good spotting scope alone is worth the money with overhead flights, without even taking a picture.
Taking pictures alone is time consuming, and takes away a lot of the enjoyment from just watching the plane.
A lot of the shots usually turn out rubbish, but sometimes pays off for the few good results.
The results will also look very amateurish compared to one's taken through a proper (usually expensive) Astronomy scope,
in combination with a digital SLR camera (not cheap) with various adapters.
I would like to go down that road, but due to funding it will have to wait.
Have a look a SkyStefs site to see how its done at the highest level :
http://skystef.be/contrail4.htm