Traffic at major East Coast airports ground to a halt Wednesday in the face of a winter storm that threatened to shatter snowfall records in several states. Thousands of flights were canceled from Washington, D.C., to Boston, with blizzard conditions expected throughout the region. Continental Airlines halted all mainline flights at its Newark, N.J., hub. Analysts say investors will likely be reminded of the storm when airlines report first-quarter earnings. "Where it's going to hurt the carriers is an increase in expenses in the month of February," says Jim Corridore of Standard & Poor's.