The ITA query language includes an undocumented feature to select
flights that use a particular aircraft type. E.g. to find flights on
an Airbus 320, include something like this:

LAX :: /aircraft t:320

By trial and error, negation can be used to exclude an aircraft type.
E.g.

LAX :: /-aircraft t:320

Suppose you oppose the CISPA bill and want to boycott Boeing. I've
found that this syntax will find flights on non-Boeing aircraft:

LAX :: /-aircraft t:734 t:744 t:752 t:762 t:763 t:772 t:773 t:777

To get the aircraft type number from model number, these sites are
useful:

https://de.flightaware.com/live/aircrafttype/
http://www.seatguru.com