Between 1968 and 1971, Pan American World Airways issued over 93,000 "First Moon Flights" Club cards to those eager to reserve a seat on the first commercial flight to the Moon. The cards were free. I was a proud member.
The Club originated from a waiting list that reportedly began in 1964, when Gerhard Pistor, an Austrian journalist, went to a Viennese travel agency requesting a flight to the Moon. The agency forwarded his request to Pan Am, which accepted the reservation two weeks later and replied that the first flight was expected to depart in 2000.
On July 20, 1969, Neil Armstrong became the first human to step on the Moon. Pan Am marked the occasion by sending members a First Day of Issue envelope bearing the new "First Man on the Moon" stamp. I was excited to get mine and have kept it all this time.
I now doubt I will make it to the moon. But it was an exciting thought.
Pan Am did not survive to find out. It went bankrupt in 1991.