The environment for mergers and acquisitions is hot right now in the commercial aerospace industry, but one of the biggest customers is trying to regulate the speed at which some of those deals are happening. According to a report from Reuters, the Boeing Co. (NYSE: BA) is using its power of approval on supply contracts to slow the speed of acquisitions — a power that allows it to act as an unofficial regulator invoicing deals among its supplier base. Boeing admits that it has the ability —…