The Difference Between Things and Thingamagigs

While BossyBoy and I visited the fountain of Frisco we decided to hang out for a little bit since the weather has finally decided to cooperate today and act like a spring for a change.
For some reason BB wanted to just chat about random stuff (he's certainly mine) and the topic came up about things and thingamgigs, according to BB there is a difference.

Things are things found on the ground, such as cars, people, and fountains that have no water.
Thingamigigs are things found in the air such as; birds, clouds, airplanes, and plastic bags hung up in electrical lines.
This got me curious because obviously some thingamgigs do eventually come down to the ground. I asked him, what does happen to thingamagigs when they come down to the ground? Duh mom, they become things.

I have now been schooled by a 4yr old. The More You Know!