Going to Pattaya by bus. Depending where you stay in Bangkok. It may be faster to take the bus from Morchit bus station rather than Ekkamai since you avoid getting stuck in a bus in Sukhumvit traffic.

Returning Pattaya to Suvarnabhumi by bus you can call Bell Travel Service Co. by dialing locally 038-370-055-6. They more or less speak English pretty well. They will dispatch a minibus to your hotel which will deliver you and your luggage to the office adjacent North Pattaya bus station where you transfer to a nice AC bus directly to Suvarnabhumi departure level. All inclusive, hotel to Suvarnabhumi is 150 Baht per person. 20-30 Baht more than a government bus but they handle getting you to the bus station and deliver you to Suvarnabhumi departure level rather than Suvarnabhumi bus station. 100% tourist friendly, very easy and foolproof.