UFOpaedia states that they have no landing gears, and that they are not VTOL enable...
IMHO, it only lacks a third light craft to make things coherent, yet balanced.
Scout : unarmed, crew of 3, can't land, only crash sites (or forced landing). 770 km/h.
Heavy scout : armed, crew of 5, can land, designed to operate ground missions : early Landed UFO, Terror and Base Attack missions.
880 km/h, One PB Weapon but light armor and less combat skills. Deadly enough when engaged one on one by any classic Terran craft.
(i.e. the same as the current fighter).
Fighter : armed, crew of 3, can't land, only crash sites (or forced landing). 880 km/h. Same design as the heavy scout, still only one PBW, but more room for added armor and tactical computing (including a CME unit, always damaged when it crashes). Deadly to any all-terran tech wing of early fighters (before laser & up is searched).
This way, there is no added model to bother with.
I know, that looks like other X-COM clones...