I did notice when travelling on British Airways flights from the USA
that the tickets were in 24 hour format. Presumably that is how some
Americans may get their first exposure.
When I transferred from a Portland-Atlanta flight to an Atlanta-Baltimore flight (Delta), I noted that terminal E at Hartsfield Intl (the international terminal, where we arrived because the plane was continuing on to Sao Paolo) had displays in 24 hr format. But when we got to domestic terminal B, back to am/pm.
cm
