I’m confused. I know to use National’s Emerald Aisle I have to book a mid-size car, but is that the only way to bypass the counter?
Great question! You’re really talking about two different services. Everyone with an Emerald Club membership can bypass the counter and go directly to the car lot regardless of car size. At some airports there is a reserved aisle for each size of vehicle and you can select any car in the appropriate aisle. In smaller airports or lots where space does not allow for this, the lot attendant will direct you to the stall where your assigned vehicle is parked.
If you are renting a mid-size car and have an Emerald Club membership you can proceed directly to the Emerald Aisle, which contains about 20% mid-size vehicles and 80% larger vehicles. Select any car you like and pay only the mid-size price.