Slitherine

in multiplayer Urban Warfare i was allowed to buy a fighter - but there are no airfields on the map.
in multiplayer Hunters in the Atlantic i was allowed to but a paratrooper - but he will not load from any airfield.

Short answer:
Both intended features.

Long answer:
In Urban Warfare, the map was designed with no air forces and no airfields. There's a serious balance issue in the quality of Late War Soviet aircraft compared to Late War Allied aircraft, so neither side has access to any air power in that scenario.

In Hunters in the Atlantic, the intention was to not have any ground units, all prestige and core slots are for purchasing or refitting aircraft, but apparently I missed Bergen which was given a city tile. So you're not supposed to have paratroopers, hence you are allotted zero air transport and sea transports, but you should also not be able to buy ground units. Bergen will be changed to other 'cities' on the map IE not actual city terrain that allows for unit purchases.

understood, but maybe the Buy Units screen should indicate units that cannot be deployed. one miss-click and there goes the tank killer I really needed <grin>.

i like balance and these are great scenarios, but i feel a bit hard done by to have to continue to play (MP) with units I either cannot use or cannot deploy.

If you cannot deploy a unit you attempted to purchase, your prestige is returned. There's no penalty.
As for restricting purchases, a necessary evil to preserve good balance as the 10 special MP maps are especially designed for balance, even if they sometimes bend history.

could you re-test the statement "If you cannot deploy a unit you attempted to purchase, your prestige is returned." - i lost my points !!

no, you missed my point in the second sentence - i was not against restricting purchases, i was upset that i bought things i could/can not use !! (see above).

Buy a unit, your prestige goes down. If you are unable to replace a unit and cancel your purchase (by clicking on a non deployment hex), you will see your prestige go back up.

As I said, you should not be permitted to buy any ground units in Hunters in the Atlantic. Will be fixed in the first patch, just need to change Bergen to a non-city tile.