Congressman Leonard Boswell is concerned the proposed merger of United Airlines and U-S Airways could hurt Iowans. Boswell has written letters to the President, Attorney General and Transportation Secretary asking them to look at the possible impact of the merger. Boswell, a democrat, says Iowans already pay sky-high airline prices, the highest in the nation.He says the bigger airline produced by the merger could hurt attempts to bring alternative air service to Des Moines. Boswell says bigger airlines put competitive pressure on smaller airlines until they collapse under the pressure.