* Houston, Nashville, Dallas, Chicago O'Hare and Newark among affected airports * More than 3,000 flights delayed, data shows, as staffing shortages widen * Air traffic controllers required to work during government shutdown but are not being paid (Adds more details on delays in paragraphs 2, 5-6) By David Shepardson WASHINGTON, Oct 7 (Reuters) – Air traffic control staffing issues are delaying flights for a second straight day at numerous U.S. airports as the government shutdown reaches its seventh day, the Federal Aviation Administration said in a notice on Tuesday. More than 3,000 flights have been delayed, according to flight tracking data, as staffing shortages have impacted a widening number of airports, including Houston, Nashville, Dallas, Chicago O'Hare and Newark. The FAA is redu

See Full Page