Mid 1940s, New York to London round trip around $600 or $7000 in today's dollars.

There was almost no coach class before 1948. You went first class or not at all.

Airfares were relatively constant from 1931 to 1970 in terms of cost per mile which was the way they used to determine ticket prices.

Fares doubled during the 1970s. Since then they have again remained relatively constant, reaching a peak around the year 2000 and dropping after 9/11.

Of course, when I say "constant" that doesn't take inflation into account.