By DAVID KOENIG
AP Airlines Writer
DALLAS (AP) — Ask anyone old enough to remember travel before Sept. 11, 2001, and you’re likely to get a gauzy recollection of what flying was like. There was security screening, but it wasn’t intrusive. There were no long checkpoint lines. Passengers and their families could walk right to the gate together. That all ended when four hijacked planes crashed into the World Trade Center towers, the Pentagon and a field in Pennsylvania. The worst terror attack on American soil led to security measures and other changes large and small that have reshaped the airline industry and made air travel more stressful than ever. The changes have also raised concerns over privacy and whether they in fact make it safer to fly.