No EWR was Never a Crew Base. In the days of PI, construction was done but it never came to be with the PI/US merger. Then Deals were done for LGA with CO and part of that deal was to down size EWR so CO could have that.Don't forget BWI which was a MAJOR base as recently as the beginning of the decade. All of MetroJet was based there. Closed in 2001 or 2002. The New York base opened in 2000 when the US Airways Shuttle was integrated into mainline operations.
Others...
Baltimore
Dayton
Los Angeles
Indianapolis
Norfolk
Roanoke
Miami
Winston-Salem
San Francisco
Greensboro
San Diego
Were Newark or Kansas City ever crew bases?
Does anyone have the year openings and closings of these bases? I think LAX closed in 1997 or 1998.