not a smart idea to start DCA-LGA (if it's even possible). they'd get crushed by the hourly frequencies that US and DL already offer.

if they could get a perimeter slot (doubtful), then that's what they should go for. a DCA-LGB flight would be interesting, as would be DCA-OAK.

personally, i think the perimeter rule is a joke. the residents complaining about additional jet noise, yet 757s and a321s are run into DCA daily.