DEMAND FOR FLAG FAbrIC RISESU.S. flags have been in huge demand and retailers quickly sold out of their stocks following the Sept. 11 terrorist attacks. Glen Raven is the largest manufacturer for fabric going into U.S. flags and the N.C.-based company has been meeting the demand.Glen Ravens Filament Fabrics makes nylon and polyester fabric which it sells to companies which print the stars and stripes on the griege fabric. A company spokesman says Glen Raven so far has met the increased demand with current fabric inventory. The company also produces a full range of fabrics for military uses.Most outdoor flags are made of either nylon or polyester or a blend.October 2001