Dosch Design (http://www.doschdesign.com) has released Dosch 3D:
Airport Vehicles, which contains 20 detailed 3D-models for the
realistic depiction and visualization of activities on an airport
tarmac in daily operation.

From airplane loading and boarding to taxiing away from the gate, to
refueling and even emergency response, it all can be visualized
easier with this new Dosch 3D-product, according to the folks at
Dosch Design. Vehicles provided include two ground luggage transport
systems, three luggage loading vehicles, two people-moving systems
(incl. Maglev-train), two access stairs trucks, as well as various
specialty-vehicles (including a tow tractor, catering truck,
fuel-truck, fire truck, snow removal truck).
This product complements Dosch 3D: Airplanes, as well as D3D:
Industrial Buildings and D3D: Passenger Transportation. Together
these products cover most features of an airport environment.

The completely textured 3D-models are provided in multiple file
formats: 3DS, 3dsmax (version 4 and above), Lightwave (version 6.5
and above), OBJ, Maya (version 4 and above), VRML, SoftimageXSI,
Cinema 4D (version 8.5 and above), Collada DAE and FBX. The list
price of this product is US$179.