Andrew Boulton
The Adminator
The Scout/Courier is the only ship that we know of in IISS service that can land. Surely you don't believe that the only ships classses the IISS has are the ones we've heard about? That's, what, Scout/Couriers, Donosevs, and AHLs? (I can't recall any other classes off-hand (I'm not counting X-boats and their tenders)). They'll have all sorts of support ships to support their operations. Transports to keep the bases supplied, for one example. J6 couriers too, I imagine, unless the IN somehow prevents that. If not, then definitely J5 couriers (Oberlindes Lines has some J5 couriers; if a civilian subsector-wide merchant company has them, the IISS certainly has them too). Transports for moving personnel in bigger job lots than Scout/Couriers can. Escorts for protecting Scout operations outside (and sometimes inside) the Imperium.
Hans
AIUI the IISS is deliberately limited to J4; only the Navy, government, and megacorps have access to better.
Most support jobs can be done using XBoat Tenders (possibly upgraded).