By Luc Cohen and Karen Freifeld NEW YORK (Reuters) -A U.S. court on Monday issued warrants for the seizure of two luxury planes owned by Russian billionaire Roman Abramovich under U.S. measures imposed after Russia’s invasion of Ukraine, court records showed. But the U.S. government’s likelihood of gaining control of the aircraft worth nearly $400 million was uncertain. A Department of Justice official said the $350 million Boeing 787 Dreamliner and $60 million Gulfstream G650 ER were not in U.S. custody, and the official declined to say if the U.S. government knows their locations. A federal …