I use Que! From Irregular Miniatures. A couple of pages, a couple of quid, one dice per player, card driven initiative. Units are 12 strong, so no masses to paint. What’s not to like?
They don’t include rules for aircraft, I included an ‘aces are aircraft’ rule, and let them do a mortar or machine gun attack on one unit. Sorted. Sometimes the cards throw up ‘paralysed’ units, but that’s war.
Recommended.