Reputation is a key feature in the Overview window.
Pax of all time: "Pax" is an abbreviation common in the airline business. Short for Passengers.
Cargo: If this is active it will tell you cargo totals transported.
Reputation: This can change for a few reasons. I go into detail below.
Pax Bonus: Earn faster by adding In Flight Entertainment to your planes when you buy them.
Reputation should be maintained at 100%
Check the STAFF tab. Is there a strike? Try increasing salary so employee satisfaction is 80% or greater.
Check MAINTENANCE for any aircraft damage. Fix any damage As soon as possible. If planes require C-Checks then give them C-Checks the next time they land. If your planes need D-Checks give them D-Checks immediately.