The one I own is light duty. The one I drive for work is heavy duty.
If you are correct that only managers are allowed overtime, then I would guess that the corporation feels that having managers work overtime pays off in the long run, that they will save the company more money than they get in overtime wages. They probably feel that other employees should not get overtime since that time usually doesn't pay off. Better to hire another employee than to have all employees trying for overtime.
There is a federal law which screws you as an interstate carrier, and they are not required to pay you an overtime rate.
All American airports are currently not allowed to have duty free stores on arrival. This is due to taxes in America being raised and changed in light of recent economic issues.
If your job is a light duty one then no. If it isn't yes.
I would not hyphenate in this sentence: "I was put on light duty." Here "light" is an adjective modifying the noun "duty." I would use a hyphen when together they form an adjective: "I was given a light-duty job."
YES They Can.
pad and pencial
There is no requirement that they allow you to work overtime. You are being allowed to earn your normal weekly amount.
no yes they should be able to participate in combat duty
The decision to offer light duty is a unilateral employer decision.
Depends on how long the light duty will continue.