Some retirees are now cashing in on the golden age for retirement savings, when benefits were more generous and investments in real estate and stocks boomed.Getty Images; Alyssa Powell/BIAmid a widespread retirement crisis in the US, some boomers are entering their golden years flush with savings.They're benefiting from now-rare pensions, real estate value increases, and stock market gains.But lower-income households face challenges with retirement savings and dwindling pension plans.If you're looking for Michael, 75, try looking to the sky.The retiree has a unique retirement side gig: He's a corporate airplane pilot.He dabbles just with contract gigs because he loves it; that's a common theme for Michael at this stage in life.