What does co-terminals really mean?
 

I have often been presented itineraries by Delta involving transfer between JFK and LGA. I suppose the airline brands them as co terminals. I have also seen DCA, BWI and IAd being described as co-terminals, although I am not sure if Delta still does that. If BWI/DCA/IAD are co terminals, why are fares different for trips originating at these airports?

From my vantage point, co-terminals are separate for all intents and purposes. Other than being able to occasionally do a routing connnecting from one to another...there is no allowance for a change between co-terminals in terms of change fees, etc.

What they really often are is "Inconvenient lapses in good sense" when it comes to travel planning and booking.

There are no feelings more desperate than a late arrival at MDW trying to make a connection out of ORD. Then there's the similar stress involved in an LGA/JFK duet, a DCA/IAD paso doble (and BWI/IAD's no stately minuet). Are FLL/MIA still coterminals? Certainly, Miami's old seaplane terminal had coterminal status with Miami's airport

Long ago, 1981 or so, only a helo transfer saved us in London after a BCAL late arrival from IAH. Arranged and paid for by the airline which always left it in a warm place in my heart, regetting its passing, the only downside was the hop to EDI aboard a BA (BOAC then?) Viscount "shuttle" apparently uncleaned since it had been used to extract refugees from some furrin airport where WCs were in short supply). Ms TMO was a bit edgy about the helo, but the scenery was boo-ful, a green English Spring in full flower.

Are there any of the old military/civilian coterminals still around? I recall Frankfurt/Rhein Main, and a switch from a military to a civilian flight in Orlando (pre-MCO) with the civlian terminal on one side of the airport and the military (Navy) on the other. Back in those "good old days", it was a short drive, the "Duty Jeep" across the runway and ramp to the gate. Weren't there were the old "rules" in Berlin, Gatow and Templehof, but civilian flights only to West German airports?

DMs are allowed to SDC btw co-terminals at no charge.