<<Isn't there a flight mileage limtation on scheduled service into and out of DCA>> Yes there is Al, but airlines are granted exemptions to operate "beyond perimeter" service, which means over 1500 (I think) miles. That is why AS has SEA-DCA, DL has SLC-DCA and there are many others. TWA had LAX-DCA for years, but TWA does not exist anymore and those slots were reapportioned for another route.