We are ending our tour in Porto, Portugal and want to travel to Madrid on a Friday in October. It appears that train travel is not convenient and/or efficient. Am I wrong? Air flights are on TAP Portugal. Anyone have experience with this airline? Any other suggestions for travel between these 2 cities?
Flying is your best option. I've read some not great things about TAP Portugal but have not flown with them. However, when you read reviews on the big US airlines, they aren't great, either! I know Iberia's offshoot - Air Nostrum flies between Porto and Madrid and I have flown with them 2-3 times. It's always been a short flight and they have been fine.
Flying is indeed the best way. Use Skyscanner to find all options: http://www.skyscanner.com/. Then do a dummy booking to find all the fees before choosing a carrier.