Is there a discount for arriving by taxi from the airport?

Yes. If you come from the airport by taxi, you get $15 cashback on your rental.

Just show your taxi receipt at the counter when you settle up. Without the receipt, the cashback can't be applied, so be sure to get one before you leave the taxi.

It can't be combined with other discounts. The rental office has no airport counter and expects guests to arrive by taxi, so this cashback gives some of that cost back to you.