Lived near a swamp some years back , a swamp buggy is a vehicle with large tires and a huge, lifted ground clearance, sometimes as much as 10-20 FEET, and usually powered by a highly modified (lots of horse power, 8-71 and even 12-71 blowers are common) V8 or Diesel.
On the other hand, an air boat is the flat bottomed boat with the caged propeller in the back as it's propulsion.
Swamp Buggies can run on dry land, in the swamps with the tires and most of the suspension lift fully submerged, climb over sunken tree stumps, etc.
Air boats can run over water, and over wet, slick marsh grass, but come to a grinding halt on dry land, saw that happen to more than one drunken driver in the past!
One idiot we knew tried to jump a levee road with his air boat, he apparently didn't know, or in his drunken state had forgotten, that since the last time he had done it showing off, the state had widened that levee road from one lane wide to 4 lanes wide.
Up the slope out of the water he went, but instead of crashing down safely into the water on the other side of the once narrow levee, he landed on asphalt, slid, ground the bottom of the boat dang near through.
Rest of us parked alongside the bank, climbed it to see the wreck.
A minute or two later, along comes a semi and flattened the airboat. $50k of boat and motor gone in an instant of drunken stupidity, and yes folks, it was preceded by "Hey ya'all, watch this!" as he was trying to impress some of the single young ladies riding in the other air boats, impress them enough to get them to ride with him.
He had lots of money, no brains, and looked like Jabba the Hut in a speedo, but the booze gave him the courage of a lion when it came to pursuing the ladies.
I though I was going to have to give my poor wife mouth to mouth resuscitation, she laughed so hard she nearly passed out from the lack of oxygen, and the single gals, who were some of her model girlfriends, were laughing just as hard.
Poor old Jimmy John McRae never had a chance with those gals, but you had to admire his never give up attitude.
Dang, that was nearly 50 years ago, where did the time go?