By David Schepp BBC News Online's North America business reporter

At O'Brien's Grille & Pub, in the heart of Pittsburgh International Airport, they no longer serve prime rib steak.

Diners are greeted by a tables set without knives

It is not because Pennsylvania has suddenly been stricken with foot-and-mouth or mad cow disease.

Rather, due to its location, within the secured area of Pittsburgh's state-of-the-art airport, O'Brien's is required by the Federal Aviation Administration (FAA) to remove all metal knives from customer-accessible areas.

"Since 11 September - because of the terrorist attacks - we no longer serve the prime rib," says Stephanie, a waitress at O'Brien's.

After all, what's a nice slab of prime rib without a knife to cut it?

Steak lovers beware

Stephanie adds that if patrons order the Delmonico steak or the house special Gaelic Steak - a 10 ounce New York Strip steak served with whiskey sauce - the chef will pre-cut their steak in the kitchen prior to it being served.

A patriotic expression on O'Brien's pub's windows

With less hearty fare, such as salads and chicken, O'Brien's includes a plastic, serrated knife - definitely insufficient when it comes to meat.

It is the sort of clearly visible - albeit subtle - change American travellers have had to endure since 11 September.

Long lines to get through security check points at airports are now all too regular across the United States.

From head to foot

In addition, the antics of Richard Reid, who tried to ignite a bomb hidden in the heel of his shoes on an American Airlines flight last month, now require some flyers to remove footwear for inspection as they pass through metal detectors.

It is the sort of hassle that has travellers shrugging their shoulders in resignation even as they complain bitterly about the nuisance.

US flyers are having their patience pushed, and the scrutiny can sometimes be doubly tedious given the vastness of the United States.

Thanks to airline deregulation, airports here operate on what is called a hub-and-spoke system, in which passengers at smaller airports pass through larger "hub" airports en route to their destination.

Tight security

That means two and sometimes three layovers for some flyers - and just as many security checks.

Thanks to Richard Reid, travellers must now remove shoes

Even if a traveller passes through security at the originating airport, there is nothing to say he or she will not be required to undergo further inspections while boarding subsequent flights.

At airport gates throughout the US, security personnel - at least one male and one female - descend upon waiting travellers, moments before a flight is to be boarded, to perform ad hoc searches.

Armed with metal-detecting wands, the inspectors, at random, select passengers for inspection as they ready themselves to board their flight.

It is these sort of hassles that are perhaps the reason the handsome oak bar at O'Brien's is filled with travellers consoling themselves with pints of ale and glasses of scotch.

Just next to the bar, a queue of hungry tourists await tables.

They might want to try the salmon - less knife leverage required.