One, during his National Guard days, involved working for Skull and Bones member Robert Gow, supposedly seekinging out tropical plants. According to Daniel Hopsicker:
"Bush himself would later refer to his time at the plant nursery firm as a dull 'coat-and-tie' job, an odd description for a position which entailed jetting to steamy Caribbean capitals chock-full of intrigue.
"The MadCowMorningNews uncovered indications that, instead of scouting Spatholottis Plicata (Philippine Ground Orchids) and Strelitzia (Giant Bird of Paradise) tropical shrubs, George W. Bush was serving a 'tour of duty' in Central America for a shadowy arm of the U.S. Government which Watergate burglar and disgraced CIA Agent E. Howard Hunt called 'Clandestine Services.'
"Bush's plant-nursin' jet-flyin' story was the future Presidents 'cover' for the unit to which the young second lieutenant was actually detached—officially or otherwise—a massive clandestine U.S. government operation that was going on just then called Operation Condor.
"Was George W. Bush working for the spooks?"
http://www.madcowprod.com/index46bb.htmlThe other was working for a small airline in Alaska in the summer of 1974:
"People who worked there recall that in addition to its aviation and construction work for the pipeline, the company flew planes that carried food and mining equipment into Zambia and ambulances into Libya. It also 'flew a bunch of F-14 parts into a town in Iran for the shah,' said Steve Scott, who worked as a loadmaster. And 'we helped build a military base in Oman.'
"The Times reported that a number of onetime employees say they found themselves doing contract work for the CIA. And the company’s President seemed to confirm their reports.
" 'I had a big reputation for doing C.I.A. work,' Mr. Bergt said. 'It wasn't deserved. We did some.' "
http://www.madcowprod.com/mc5022004.htmlMy own guess would be that Bush Sr. was trying to get Jr. into the family business and he just didn't have what it took. But who knows?