Folks,
I live fairly close to Heathrow and see a lot of aircraft pass over at around 7000 feet.
Does anyone know of any web sites that show aircraft shapes as seen from below, main area of interest is identifying commercial aircraft so really only covers a handful of planes.
Geffers
Might be better to buy a book, then you can take it outside with you. Search for “Aircraft Recognition” and you should get plenty of hits.
Thought initially of a book but how many various aircraft would warrant a book. All I wanted to do was recognise the various Boeings and Airbus which is practically all commercial aircraft.
True the book can be outside and that is a bonus.
Geffers
Also who knows where your interest may lead, aircraft can be very addictive.
If you are only interested in a relatively small number of modern aircraft you can take your own photos.
Use your phone browser to monitor your Skyview as a plane flies directly over. Stand outside and photograph the underside of the plane.
Use Skyview to link to Flightaware for that aircraft and put that info on the photo.
S.
Ps. You could then publish your own book entitled " The underside view of planes that land at Heathrow" 
Good suggestion 
Geffers