Can a Class A tractor be driven with a Class B license

Yes.
Just pay attention to what fmcsa told you.

You could ask truck drivers what color the sky is and get 22 answers..

 

An old thread on the subject.

Can you drive tractor with class b

 

The only thing that would prevent you from driving it is if you don’t have an air brake endorsement.

 

Keep in mind, a Class B truck, even unladen is a much safer vehicle to drive than a bobtail. Even on a double-screw 3 axle truck, the box or the bed adds enough weight onto the drives. A bobtail is a handful to drive at best. Take this from a guy who used to drive a cabover 120km up the Autoroute in Quebec in the middle of winter. The nearest thing I've driven to that is one of those old penny-farthing bicycles from before 1900.....

 

Truck drivers are not the authority on what the FMCSA regs mean. No DOT officer is going to accept "but some truck drivers on the internet said this was legal."

The tractor almost certainly has air-brakes. So if you don't have an air-brake endorsement before driving the tractor you are not allowed to drive the tractor and need not consider anything else. It's not a matter of you feeling comfortable. It's a matter of your license and the endorsements on your license.

The 383.91 guidance you link to is showing me that you can drive the tractor (if you have air-brakes endorsement on your Class B) but you cannot have ANYTHING in tow or "no attached unit." If you connect so much as a child's little red wagon or skateboard and you touch a public road your are in violation.

 

THIS IS CORRECT!

You first have to lose the idea of what a tractor is and what a truck is. It is all trucks.

A class B license allows you to drive any vehicle up to and over 26,001 lbs GVW - ANY VEHICLE.

THIS ALSO ALLOWS YOU TO TOW ANY TRAILER WITH A GVW UNDER 10,001LBS.

The class A license allows you to drive any vehicle up to and over 26,001 lbs GVW AND TOW any trailer up to and over 10,001 lbs gvw.

Most truck drivers don't know anything other than holding a steering wheel and try to keep the truck inbetween the lines on the road.

 

What @Ridgeline said. And I will say in my experience most DoOT officers are not the authority on the regs either. Been many cases were they interpreted regs wrong. Most problems we encounter is so called equipment regs. What was only required for the year model at hand. Not what is required in 2025. Blows their mind. Lol.