It was later converted into the prototype CRJ1000 by replacing the fuselage plugs with longer plugs .
The first CRJ900 ( C - FRJX ) was modified from the prototype CRJ700 by adding longer fuselage plugs fore and aft of the wings .
CRJ700 was later converted into the prototype CRJ1000 by replacing the fuselage plugs with longer plugs .
The first CRJ900 ( C - FRJX ) was modified from the prototype CRJ700 by adding longer fuselage plugs fore and aft of the wings .