As the topic says, what prototype bomber, fighter, transport or jet do you wish had seen squadron service during the war, and why?
Personally, I wish that the single stage Merlin engined Whirlwind prototype had gone into production. If it could do 360 mph on those anemic little Pegasus engines, imagine the performance with a pair of 1200 hp Merlin XIIs.
Whirly Mk IIs would of been great, its such a pity that the fluffed up the design so much with the Welkin. Clip the wing tips, add a semi-recessed centerline bomb mount, keep it below about 20,000 feet and give it a belt feed for the Hispanos, even if you have to sacrifice one of the cannons to pad out the ammo capacity.
The other great British 'also ran' for me was the Martin Baker MB.5. If only because it looks like the msibeggotten love child of a P-51D and a Griffon engined Spitfire
EDIT: NO paper planes! It must have at least been built in prototype form and either been ready to fly or have flown. Otherwise this just degenirates into a Luft'46 thing.