My first ever holiday abroad was Tenerife. We flew from Gatwick with British Airtours, which was the charter subsidiary of British Airways. This airline had been created from British European Airtours, who had operated the Comet 4, on the creation of British Airways. The Comets were phased out in November 1973 and replaced by the Boeing 707. This is what we went on (though I don't know the registration).
http://www.airliners.net/open.file/406478/M/
We flew at around 40,000 feet, and apparently it was quite a clear flight (we were flying in November).

This was taken by my Mum inside the 707.

This is the view we had through the 707 window.
I enjoyed the flying, and when we were in Tenerife we booked a day trip to El Aiiun in Spanish (now Western) Sahara. We flew with Iberia on a DC9, which at that time was rear loading instead of the usual airbridges. My Mum said all the other passengers let us get on the aircraft first, but I don't remember that. We flew via Las Palmas, where we had a delay because of fog in El Aiiun.

This Boeing 727 of Iberia was taken in Las Palmas.

A four year old spotter learns the trade!
An Iberia DC9 in Tenerife North Airport
http://www.airliners.net/open.file/435203/M/
I really loved my first holiday by air, and the following year we flew to New York with BA for my first ever 747 flight.