Keep your eye on that grand old flag, if you can find one.

Area vendors say they can't keep American flags in stock, as more and more people are displaying the red, white and blue outside their homes as a symbol of support for U.S. troops in the Persian Gulf War.

At the National Capital Flag Co. in Alexandria, the phones keep ringing, and there is a steady flow of customers coming in to buy the nylon 3-by-5-foot flag that sells for $31.60. Normally, the company sells most of its flags to other businesses.

"They're going as fast as we get them in. We're a day behind in shipping," said Elizabeth Harrington, company vice president.

"I've been with the company 25 years and I can't remember ever being bombarded with orders like this. Our sales are up about 75 percent," she said.

Yesterday, Albert G. Feneis, of LaPlata, Md., dropped in for the Stars and Stripes.

"My stepson is in the Army Reserve and . . . he leaves tomorrow night from Fort Benning, Georgia, to go to Saudi Arabia. This is my way of supporting the idea of him being there," said Feneis, a technical director at Integrated Systems Analysts in Shirlington.

"My wife and I will put it on the front porch. I got a big yellow ribbon to hang down from the top of the mast," Feneis said. "In fact, my son will call tonight, and I hope to tell him the flag is out."

This sudden popularity caught stores by surprise and with few flags in stock. Usually, Old Glory stays packed away until Memorial Day or the Fourth of July, when the patriotic fever hits and flag sales fly.

But now, in the dead of winter, sales clerks at Sears in Arlington and Hechinger stores said the American flag is sold out, and they're waiting for shipments.

"We've sold out several times," said Sally Courtney, senior vice president of merchandising and marketing at Hechinger headquarters in Landover. "We just took new orders and will be resupplying this week. I've been here 20 years and it's never been like this."

Courtney said the store's best-selling flags are the 12-by-18-inch for $1.59 and a kit with a 3-by-5-foot polyester flag and a six-foot pole with an eagle on top, which sells for $12.69.

At National Capital Flag, business hours have been extended. "We normally close at 5, but we've been staying open until 7," Harrington said. "On Saturdays, we were open 8 to 12:30, but at 6 p.m. now, the phone is still ringing."

Late this week, people started calling to ask for flags of the allied countries too, she said. The company has ordered "a peace flag" that says, "We Support You" and has a yellow bow on it.

"We feel good about this," Harrington said. "It goes without saying, we all want peace . . . . People feel so helpless. Flying the U.S. flag is what they feel they can do."