Been awhile since I read about it but I think they are referring to the segment lengths that are allowed out of both DCA and LGA. Similar to the Wright Amendment when IAD and JFK wore built they restricted the amount of long haul (transcon's) that could be done in and out of these airports to encourage airlines to utilize the brand new airports just down the road. If they lifted this restriction with no change to the slots then Many more long hauls would replace the current east Coast shuttles. Not to be confused with "The Shuttle" I mean a lot less BUF, ROC, CAE, GSP, GSO, etc

http://en.wikipedia.org/wiki/Ronald_...r_restrictions