He arrived Friday afternoon at the airport in Rzeszow, the largest city in southeastern Poland, where some U.S. troops are based about an hour's drive from the Ukrainian border.He will be in Warsaw on Saturday for talks with Polish President Andrzej Duda and others.... The Polish leader was to welcome Biden at the airport on Friday, but his plane was delayed by a technical problem. The European Union says some 3.5 million Ukrainians — half of them children — have fled the country, with more tha