I suggest a feature that allows squad members to request vehicles directly from the commander.

This would help reduce command channel chatter for requests, as well as help players get requests through when squad and or command channels are busy or the SL is unresponsive.

This could be implemented as follows:

For the player:
. Vehicle production structures provide an interaction menu that can be accessed by players similar to the pop-up radial menu on vehicles.
. This menu provides a listing of available vehicles and displays their costs, and possibly a summary of the vehicles characteristics (for heli variants that require explanations for example).
. To request a vehicle the player simply selects it from the radial menu and confirms the request, similar to how you would select an item in the individual rearming menu of an ammo box.
. There is also an option to cancel your current request.
. Each player can only request 1 vehicle at a time, and a cooldown of 1min between requests prevents spamming.
. When a player adds a request, a hud widget displays that the request is currently pending.

For the commander:
. Vehicle requests appear in a scroll list in the commander UI, displaying the vehicle requested, the player name and squad requesting it.
. The commander can right click on these list entries to either approve or deny the request.
. Approved requests are added to the vehicle construction queue, and the requesting player is notified in their hud widget.
. Denied requests are removed from the listing and the requesting player is notified and their request widget is cleared.

Optionally vehicles constructed based on requests could also be made only accessible to the player or squad requesting it for 1 min, preventing the common issue of "x stole my vehicle".
This optional feature could even be made toggle-able by the commander via a check box above the request list widget, since it may not always be required/desired.

In addition to this system, a widget could be added for players standing close to the production structure that displays what vehicles are currently in the production queue, to provide insight into what is currently being constructed. This would reduce the need to ask the SL / CMD if "x" is actually being built.