Pam Am flew to Bombay from Frankfurt, usually with a 747-100 as well as
to Delhi. For a time, the Delhi flight operated DEL-Karachi-Frankfurt-JFK.
This was flight 73, and it was hijacked back in the 1980's for a few days.
Trans World Airlines flew the route via London Heathrow but I do not think
it was as successful as Pan Am's operations.
Today, Delta flies to Bombay via Frankfurt, with a 767-300 or an MD-11.
United was operating round the world flights, LAX-JFK-LHR-DEL-HKG-LAX
and suspended the service in 1998 due to the Asian financial downturn.
The LHR-DEL flights were operating with a 767-300ER. United is resuming
the route in November 2000, this time operating it as LAX-IAD-LHR-DEL-
United had also wanted to fly ORD-DEL nonstop, with a 747-400, but it
thought the route was too long to fly and therefore not feasible.