"The sightseeing and air tour industries contend that requiring a Part 119 certificate would cause thousands, not hundreds of small operators to go out of business. Because the FAA likely underestimated the number of small Part 91 operators and failed to provide accurate data on Part 91 operations, revenues and costs, Advocacy believes the industry's estimate may be sound. Consequently, the actual incidence of business closure is likely to be significantly higher than estimated." Source: Statement from the Small Business Administration's Office of Advocacy, which has landed firmly on the side of the aviation industry when it comes to proposed FAA rules on sightseeing and charity tours.