By by the way, the new Star Alliance booking tool on TK’s website, CAN book United flights with domestic segments, but it has numerous bugs and only a handful of routes are currently showing. Moreover, I was not able to find any itineraries which include business class travel. On the flip side, the United flights which are showing has only about $50 in surcharges for RT. It’s over $500 for RT in economy on Lufthansa. Go figure.