>Could an aircraft find itself flying too fast or slow because of changes in wind speed?
In a word.... YES!
>Windshear can be an extremely serious situation having catastrophic results.
>To cite an example of the top of my head is the Delta L1011 that crashed across the
>highway at DFW after flying into a shear caused by a thunderstorm. The shear createded
>a situation where the planes airspeed had been low enough not to be able to further
>support flight and the L1011 simply fell out of the sky.
Not quite accurate. The plane had plenty of flying capability left, but the pilots were not trained in the proper technique to utilize that capability nor in recognizing when to utilize that technique. This was the "final straw" that forced FAA to _require_ windshear simulator training at Part-121 airlines. I've flown that exact scenario more than a dozen times in simulators and escaped every time (average at AA has been ~65% success rate). Probably because I got so d*** scared each time that I squeezed every ounce of performance the plane could provide. Probably burned up a couple of engines along the way as well.