Hope this doesn't sound too rookie, but if you make a cash withdrawal from an airport ATM, say for example 200US, will it give you large bills that may be hard to cash? Or would it be better to make more smaller withdrawals. Just don't want lots of service fees on my card

Which country? If you are using an ATM in Asia you would be putting the amount to withdraw in the local currency, the size/amount of notes you are likely to receive would depend on the country you are withdrawing in.

some would be large, certainly all would be larger than you would want to give anyone as a tip for instance....just as in the usa or europe, you do not get $1 or 1 euro bills....
in thailand for instance the bills would be large enough so that you might have a problem paying a taxi with them as the taxis rarely can even change a 500 B note....you just have to break it down by buying some candy in a shop or getting change at your destination (hotel)....

for instance i usually withdraw $300 each time in thailand....that would be approximately 12000 B....i think it would give me two 5000 notes and two 1000 notes or maybe 12 1000 notes....usually machines have room for two denominations but some hold more...you would never get 100 B notes for instance...

Enter an amount that will require smaller bills. Instead of 20,000 yen, punch in 19,000 yen. Instead of 8000 baht, use 7500.

Or exchange a $20 or $50 bill and ask for small bills. With such a small amount there is little reason to be concerned about the exchange rate. And you don't have to run around trying to find change for the big bills.

We've found that when using ATMs more than likely you will get large bills in most countries... certainly larger than you will need for a taxi or bus or a tip. But at the airports, we've found that next to almost every ATM is a Currency Exchange booth... where you can break a larger bill to get you started. Don't be surprised if some of the agents aren't all that agreeable, but if it's only one large bill, you shouldn't have a problem. If this fails, buy something at a newstand or nearby shop.

You've all been helpful. Looking to get Thai Baht at BKK airport before taking a taxi upon arrival in HKT. Not too concerned about the exchange rate, just don't want to make lots of withdrawals b/c there's a fee each time.
Then don't want to have a problem paying cab driver on the first few hours in Thailand. We can try making change at the Currency Exchange booth Sandi suggested.