Iowa Senator Chuck Grassley says he would prefer to see the Iowa Air National Guard in Sioux City retain its F-16 fighter planes. Federal officials have proposed replacing the fighters with larger tanker jets. Grassley says it would be better to have the tankers rather than no National Guard presence in Sioux City.Grassley says if the tankers do come to Sioux City, it looks like the Department of Defense would pay for improvements at the airport to support the larger planes.City officials say they expect to hear a final decision from the Defense Department next month. Fighter planes have been based at the Sioux City airport for the last 50 years.