Here are a few of my scratch-built aircraft.
These were not "kit bashes" -- not made by modifying an existing model, but rather from scratch. I sketched out forms to scale on paper, used them as guides to cut card board, and puttied-in and sanded the bodies to shape.
All were made back in the '70s and early '80s. I think I made the last in about '82. That was about the point where I realized the terrible skin rashes I was suffering from were an allergic reaction to the plastic modelling putty. So I had to stop making scratch-builds.

First is a P-39 Airacobra. Didn't quite get the focus right on this pic. Sorry. But my old 'Cobras are veterans of many wargames from decades ago. Certified Panther-killers they were. (More recent readings have clarified to me me that the 'Cobra's 37mm cannon was useless against armor -- shhhh, don't tell my old high-school buddies that!)

Lavotchkin La-5s. The heart of my anti-Stuka defenses.

Turning to modern, we have some French Gazelle Helicopters with a Mirage III providing CAP. I first made the Mirage for gaming the '67 Arab/Israeli war. Gazelles were originally concidered for a modern Jugoslavian force. Later I started picking up modern French stuff, and they were repainted.

MiG-21s in air-to-air livery. These babies actually managed to chase away some F-16s in a hobby-shop pick-up game years ago. Seems my opponant had air-to-ground ordinance hung all over his planes -- not a one was set-up for air-to-air.
It might be fun some day return to scratch-building to see if I could better my skills. But there is much less incentive these days -- when I did these models, not a single one of them was available commercially.
I had a virtual monopoly on airpower in many games when I was young. So much so that I also scratch-built Stukas, Me-109s, and even an He-111 to sell to an opponant (if I recall correctly) back in about '75. Wonder what ever happened to those old birds...