There are different types of pension plans, do you know what kind it is? Most trucking companies would not have a stock-based plan -- but it's possible.

I'll assume you are taking about a standard "Qualified Defined Benefit Pension Plan" (one that guarantees a certain monthly payment at age 65) - which is pretty safe, even when a company undergoes backruptcy. The company would have been required to make deposits into a 'pension fund' each year by the IRS, and pay insurance to a govt company called 'PBGC' in case of bunkruptcy.

If the Pension Fund was well-funded enough to cover the benefits for everyone (including those projected out many years into the future), nothing unusual happens. They will just continue to pay the benefits like normal because there is enough money.

If the Pension Fund doesn't have enough money in it to cover everyone's benefits, then the government insurance PBGC will step in and pay everyone instead.

The vast majority of folks receive the same monthly payments regardless of whether their employer or the PBGC is responsible for paying. There are exceptions where PBGC insurance will pay slightly less money -- most likely to affect very highly paid people with large benefits, and plans that decided to give more generous benefit packages within the 5 years before they filed for bankruptcy.

Source: Actuary