This is very interesting. Service to Lisbon has been increasing recently, for example, UA went from a 757 to a 767 for their route to Newark this summer season. I recall flying that route on a 757 during absolutely terrible turbulence over the Atlantic – although this is not that rational, I’m staying on bigger planes across the Atlantic from now. I’ve heard that Lisbon has been improving it’s infrastructure lately which should bring a boost to tourism (it wasn’t that nice of a place when I went back in 2013). This route really makes sense only for people traveling to/from the bay area and Portugal. For most destinations on Star Alliance would be easier in Newark if flying from Lisbon to the US. Frankfurt/Brussels/Vienna/Zurich/Dublin (United’s partnership with Aer Lingus) if you are coming from the US (destinations outside direct flights) to other destinations in Europe due to the fact that Lisbon is in the South of Europe and doesn’t make as much sense to connect there than locations farther north.