 At least two Brazilian airlines and planemaker Embraer SA have hired investment banks to help with talks with state development bank BNDES for government support, sources with knowledge of the matter said. Embraer has hired Itau BBA, the investment banking unit of Itau Unibanco Holding SA, two sources said. Embraer is seeking credit lines between 1 billion and 1.5 billion after a deal with Boeing Co fell through. 