SAN FRANCISCO (AFX) - US airlines, which are already suffering the effects of a slowing economy, will likely see their fortunes sink further as a result of yesterday's unprecedented terrorist attacks in New York and Washington, analysts at Deutsche Banc.Alex Brown warned. "The recent scale back-in (US) GDP growth numbers coupled with unprecedented fears about terrorism by US passengers are not going to bode well for airline stock performance in the coming months," Deustche said in a note to clients. The broker said the terrorist strikes, in which hijacked passenger planes were deliberately crashed into New York's World Trade Center and the Pentagon, would scare many consumers into cancelling holiday plans and avoiding air travel altogether. "Yesterday's horrific events are most certainly going to reverberate and negatively impact many industries, including air travel," it said. The broker said while an analysis of past air disasters shows that airlines' financial and stock performance held up pretty well soon after such incidents, yesterday's events are of an entirely different magnitude. "The magnitude of terrorism's impact on American travelling is likely to be greater this time around, given the fact that this terrorism has hit US soil, instead of abroad," it said. Yesterday, the Federal Aviation Administration grounded all US flights after terrorists hijacked two passenger jets each from American Airlines and United Airlines. The events will heap further pressure on carriers, who have already seen huge losses arising from the slowdown in the US economy and other key markets. Earlier this month, AMR, the parent of American Airlines, warned that losses for the current quarter would be wider than last quarter's 105 mln usd loss as the slowdown in the economy and rising fuel prices continue to weigh on its finances. UAL Corp, which owns United, also expects to post a loss this year. And with economists warning that yesterday's events are likely to push the world economy closer to recession and spark a surge in oil prices, prospects will remain bleak for all major carriers. "We were already getting cautious in the past few weeks and this adds another concern to our group (of companies)," Deutsche said.