How would you "encourage US domestic carriers to change the way they operate so that they can match the Norwegian fares while retaining American jobs." I think the point is that that is impossible.
They don't fly out of regional airports at least in NYC I think that is rare.
I"ll bet there are a lot of operational issues.
Delta, United and others own low-cost carriers (the famous United case where the senior was dragged off the plane screaming and kicking was not on United but a low cost fully owned subsidiary carrier of United) as it is, so they could have a low-cost carrier that travels to Europe. These low-cost wholly owned carriers are domestic only.
But none of them have them because they want to cannibalize the higher fares charged. They enjoy their margins.
Norwegian (like Amazon, like Uber) is in a contest to capture market share and thus may be willing to operate on thin margins or even take a short term loss to capture share. The major American carriers may not want to invest the money to retain share and prefer to use politics instead.
United does not own Republic Airways and they are not a subsidiary of United Continental Holdings (United's parent). Republic is its own airline operating flights under contract for United, Delta and American.
The legacies by and large do not own the regional carriers, nor are those airlines intended to be low-cost carriers. The differences primarily lie in the aircraft operated and result from union contracts that inhibit the legacies from profitably operating smaller (non-mainline) aircraft.
> "and result from union contracts that inhibit the legacies from profitably operating smaller (non-mainline) aircraft."
And it is these union contracts then that keep the US carriers from earning such low profits.
United Express is nothing more than a brand serving as an umbrella for a group of subcontractors.
These subcontractors seems to run with lower operational expenses and yet use Americans as pilots following FAA guidelines. United could have a similar arrangement with lower operational costs for overseas flights.