Good/Best Airlines from US to Portugal

Since you need to change planes, I would recommend to do so in Europe rather than the US: it is much smoother, as you don't need to pick up the luggage at your transfer point on the way back if you change planes in Europe. If you do Cabin luggage only, this is less of a factor, but still, I find a 12 hour flight followed by a 2 hour flight to be less tiring than 5+7 hours. So I'd look at flights from Los Angeles.

Starting from there... There is little difference between airlines in economy class, so I would go for the cheapest. I would, however, avoid booking Norwegian more than 3 months ahead, or make sure that I am covered / insured in case of bankruptcy. Which is too bad given the amazing fares.

I would, however, avoid booking Norwegian....... in case of bankruptcy. Which is too bad given the amazing fares

Really not a mystery that the two seem to be related.

In my unscientific view, the widest choice of options can be found at matrix.itasoftware.com
It is a Google company and contains more information, I think, than its cousin Google Flight. However, all it offers is info; no tickets are sold. But that data can steer you to the airline where you want to purchase the flights directly.
No stranger can guess what you consider 'good/best'. In the cheap seats, the amount of difference between airlines is relatively small and only you can decide what combination of price and schedule you prefer. Once you have a couple of possibilities you can come back here to ask for specific details of service.

There's something about researching someone else's travel that appeals to me. I can't explain it - but I do this, frequently.
I fly Norwegian Air Shuttle all the time - as recently as last week (non-stop Barcelona to Oakland - a flight they no longer offer, by the way - giving some credence to the "beware of Norwegian" crowd). I also flew TAP (Air Portugal) while in Europe (Bilbao to Lisbon and Lisbon to Madrid) - nice ride,
OK.....flights from LAX to CDG (Paris) non-stop on Norwegian - from November, 2019 thru March, 2020 are available for as low as $199.90, and they bump up to $219.90 into the first week of May. Flights on TAP from CDG to Lisbon (LIS) start as low as $37.
So - you could fly from Los Angeles to Lisbon (using these options) for under $250/person one way.
But....it is critically important that you understand two things:
1. These are the most basic fares offered by either airline. There are restrictions on baggage (10 KG - and it must be carry-on), no seat selection and no food provided.
and
2. Norwegian is in financial difficulty - although their employees claim their company will "fly through it" ( as one flight attendant told me last week) Not exactly gospel, but it offers a little hope.
So - "Good/Best Airlines from US to Portugal"? For me it's the flights that gives me the best value (but also the ones that continue to stay in business). Would I fly the route I'm recommending? Absolutely! I hope this helps.

These are all excellent suggestions, ideas so I thank all of you. We hope to fly Premium Economy since my partner is 6'4".

For an extra $95, one can "seat select" exit row on Norwegian (and get 20 KG of checked luggage and meals). I'm 6'6".....and that's where you can find me on a Norwegian flight.

If you can accept a short connecting flight in California, TAP flies from San Fransisco to Lisbon.

Badger......you are correct - and I appreciate it. Thanks.

I recommend TAP Airlines, too! We flew them twice; they were on time, decent food, and great service, and very reasonable prices. And they are not having financial difficulties.

On a recent trip, we flew Boston/Lisbon/Marseille. When we landed in Lisbon, we discovered our flight to Marseille was cancelled because of air traffic controllers strike in Marseille. TAP booked us on a flight the next day. They paid for us to be transported to a Lisbon Airport hotel, gave us food vouchers, and transported us back to the airport the next day. Great service!

Due to convenience (west coast) and frequent flyer miles we flew to Lisbon on Delta. We chose TAP airlines to fly from Porto to Madrid. It was a positive experience. We purchased tickets months in advance. It was affordable, on time and great customer service. We would fly TAP for a future flight.

matrix and kayak are great websites to check for airfare.

Connections to Lisbon from Atlanta required going through either Madrid or Charles De Gaule in Paris.

Another vote for TAP Portugal. On their longer haul flights, they use their new A330-900neo with an improved entertainment system and pretty decent legroom, even in economy. The seats have a pretty good recline in economy too. Food was decent as well, although I wanted a snack between meals and there wasn't much around, so bring some crackers or something. All in all a very good flight experience. Have an awesome trip.

I am booked on the Easter RS Best of Portugal trip in early April. I looked at both Norwegian Air and TAP but decided to go with KLM out of SF via Amsterdam. Having flown through AMS several times I know the lay of the land. I do agree with the comment about changing planes in Europe rather than the US. I was also concerned about Norwegian Airs viability, but did see an article recently that they had received a 2 year extension on some major loans. Good hunting!

Has anyone flown Tap’s sister airline, PGA Portugalias? It looks like a regional carrier.