Regarding flight numbers for most airlines, westbound and southbound flight numbers were always odd numbers and eastbound and northbound flight numbers were even.
That has changed, not sure why. I wounder which flight numbers have existed flying the same route for 29 or 30 years. AA 1 JFK-LAX has been around a while. UA 711
was ORD-LAX for many years not now. CO likes to use 1492 IAH-CMH.