ATM's Glasgow International?

If you must, can you get some from your home bank? Probably better than an airport exchange service, but if you have to, even that will work. Its pretty standard advice to avoid those exchange services because of high fees, but if it helps reduce your stress level than its worth the cost. Just get small amounts. I'd use one here at your departure airport, if its handy, so you dont need to worry if one's open on arrival in Glascow.

If you absolutely have to have some cash when you arrive - to tip a driver, porter, etc - then get a very small amount at an exchange service. Then go find an ATM when you get to your hotel.

Before I start a tour I type in the hotel name or address into Google to get the small map of where it is. Click on that and use the Nearby button to search for ATMs near my hotel. I look for ones that are in or part of banks. Also ones that are on the right network for my card e.g. Plus. I use the same Nearby function to find restaurants, laundromats, etc.

Or both Visa and MasterCard websites have ATM locator search functions.

Having just done so, you can pay contactless credit card for the bus, and find ATMs downtown. The bus prefers, if not demands, this.

You are highly unlikely to get Scottish pounds from a US bank, you will, however, get Uk pounds which are legal tender in Scotland alongside the currency issued by Scottish banks. While Scottish pounds are legal tender throughout the UK you would likely have issues trying to use them them outside of Scotland. I like to have £50-£100 cash in hand on arrival in UK.

Thanks to all for all the quick replies! Very helpful advice.

I am going to add one more piece of advice. Go slow on getting cash. Almost all transactions can be done by card. As long as you have a card that doesn't charge foreign transaction fees, this is usually the most economical way to go.