There are smaller aircraft that can get out of 7000 feet and make most east coast US airports. The 737-700 and Airbus A319 come to mind. The new E190/195 would work also. I suspect that is what they hope to get at EIS. The remaining 757's could do it also. The 757 can operate out of Orange County Airport with 5700' of runway and go nonstop 1800 miles with a full load!
What is the status on the extension? I never heard how long they plan to make it.