At Heathrow, planspotting gallery, father and son looking at BEA Tridents (I'm giving my age away).
Son : "Dad what's the difference between a Trident 1 and a Trident 2. "
Dad : "The Trident 1 has one engine ....."
Overheard at CPT :
"The London-Cape Town flight is always faster than the Cape Town-London because it's downhill."
"Yeah, and the petrol in England is better."