Access airport lounge with Gold/Premier credit card

I believe it depends on both the credit card you have, and the country it was issued in.

Taking one example, if you have an American Express Platinum card then you get access to quite a few worldwide lounges at any time, and several airline lounges when flying with that airline in any class. The current list of lounges for US customers is here. The country thing does affect you - while both US and UK card holders (as an example) get Priority Pass lounge membership, I'm told that it's at different levels. As a UK card holder, you get a priority pass card that works anywhere in the world. If you're a US card holder, then your priority pass is a "select" level one, and isn't valid at most lounges inside the states.

So, depending on what card you have, and what country issued it, and what deals are currently on offer, you may or may not get free access to one or more lounges in any one airport. What you'll need to do is check with your card issuer before you go. (They'll hopefully have a website with the details). Also, one thing to be aware of is that if you get some sort of free Priority Pass membership, you almost always have to carry the Priority Pass membership card with you. That means you need to have filled out the form your credit card company gave you, sent it back, waited for the card to turn up, and then carry that with you in addition to your credit card. At most PP lounges, no PP card means no access, no matter if you have the card that offers the free PP membership with you.

Finally, if you won't have free access to a lounge in the airport, you can often buy a pass. Priority Pass for example will normally sell you one for their lounges, and there are lots of websites that'll sell lounge access, typically for 3-5 hour visits. You can't buy access in all airports (Heathrow Terminal 5 is one that has no pay for lounges - it's One World status or Business+ tickets only), but in most airports you can buy access to at least one lounge (normally not the best one...) for not insane amounts of money.

From Master card official site about "Priority Pass™ Airport Lounge Access" (for Black Mastercard):

How Priority Pass works: Before traveling, cardholders can log on to http://www.prioritypass.com and view a directory of airport lounges available worldwide. Eligible cardholders present their Priority Pass membership cards to gain admission for themselves; guests are permitted at the discretion of each lounge.

For any questions please contact MasterCard Assistance Center at 1-800-307-7309.

I used my Amex Platinum card to pay for lounge access to American Admiral club when traveling on LAN with a 9 hour layout in JFK (and hence could not get in on the free Amex Platinum when you have an AA ticket) and Amex reimbursed the $50 fee as part of their program to pay for upto $200 per year of airline incidental fees such as baggage fees. You have to register your airline of choice for the year with Amex before you travel to get this benefit.

BTW I was not expecting this reimbursement - it just automatically turned up on my statement along with a reimbursement for my overweight bag fees. Thanks Amex!