That's an interesting question. I'm not a lawyer, but I'd be interested in the answer. From a technical perspective it seems that they'd need significantly more control over product liquidity generally, rather than locally, for it to apply; from a moral perspective it doesn't seem like a reasonable appellation at all and that the closest equivalent is labor organization--and it's worth noting that companies are not obligated to negotiate with labor organizations on behalf of contractors in the same way they are employees, but contractors are allowed to organize. Contractor labor, such as SAG, IATSE, etc. do it regularly.

Practically, the impact of a hundred airport drivers deciding to "strike" is so small that a non-mendacious prosecutor probably wouldn't even look at it. But there's a lot of mendacity around Washington, so who knows.