Looks like Star Alliance carriers have a fare attack on SkyTeam in Amsterdam, Brussels and Lyon, France with sub-$400 round trip tickets on multiple Star Alliance airlines to cities across the USA including Atlanta, Newark, New York JFK, Las Vegas, Orlando, Fort Myers, Minneapolis and Chicago. These ticket prices are for departures from January 10 to April 6.
Note: these low fares are round trip travel starting in Europe and flying to USA.
Ticket prices are significantly more when starting travel from USA airports on these same routes. Tickets originating in Europe are good opportunities for nested tickets with a round trip ticket from the USA to Europe to plan two trips to Europe.
Many of the ticket prices found on Google Flights re-priced in the $600s to $800s. I found some United.com tickets which priced in the $300s. There were many more low fare dates available through online travel agency sites in the $300s for tickets that priced hundreds of dollars more on United.com.
OTA SchipholTickets.com United Airlines / Lufthansa (found through Momondo.com search)
Amsterdam – Las Vegas
United Airlines Amsterdam AMS – Washington IAD – Atlanta ATL – Houston IAH – Amsterdam
United Airlines Brussels – Chicago – Las Vegas – Chicago – Brussels
Expedia.fr ticket Lufthansa Airlines Lyon LYS – Frankfurt FRA – Atlanta ATL – FRA – LYS
$419.75 USD (396.58 EUR) Thu March 2 – Thu March 23 (This ticket priced $618.68 through Google Flights).
Momondo.com meta-search of OTA sites
Air Canada / United Lyon, France – Montreal YUL – Orlando MCO – Newark EWR – Lyon LYS
$371 USD round trip Thu March 2 – Thu March 23
TravelGenio.com ticket price actually came out to 371.04 EUR = $392.64 USD
There are some good fare deals available on Star Alliance carriers from Amsterdam, Brussels and Lyon to several USA airports. Finding these deals through United.com is a bit of a challenge, but these deals are widely available through online travel agency websites for travel January to April 2017.
I used long trip dates with the idea of nested tickets to Europe for US residents. Of course these fares can be booked as one week trips for Europeans wanting a short trip to the USA.