For sure you can put 28s on them, but the question is whether or not that’s a good choice for aerodynamic benefits, and the answer is probably to almost certainly, no.

I’m not a Mavic expert, but do know they were very late to the wide game. Those wheels were, at some point, 13.5mm internal, 19mm wide external. Dunno if that changed at some point and yours could be wider, so you should probably measure.

But going with what we know, No: 28s would be terrible for aero on those. Even 23s would be lousy from that perspective, creating a step-down at the sidewall/rim interface, something that’s quite the spoiler to laminar airflow.

If those ate what you’ve got, I’d abandon concerns about aero effects, and just put the best and widest tire the frame will accept in hopes of minimizing rolling resistance.