Despite the volume UNK mentioned Chik Fil A has the fastest most efficient drive through system in the industry. The have multiple associates outside with mobile tablets taking orders and card payments at the start of the line, next they have associates outside handling cash payments and receipts for the card payments at a cart or stand. Then depending on drive through volume you either get your food at the window or a third set of associates brings your food from the window.
Chik Fil A Drive thru has become so synonymous with efficiency that it was referenced in complaints about COVID testing processes.
These videos show them in action: