I do it all the time, even when I get up to a fleet of 800+ aircraft. That's a D-Check every three game days, on average
With some pre planning it's not that difficult and I DO like to micro-manage. You just need a couple of spare aircraft of each type (maybe three for "Very Large" Aircraft which take longer). I try to keep six months ahead of the due dates to give me a buffer. I also plan carefully - such as only buying aircraft when less than 16 years from end-of-game and trying to avoid buying stuff between 10 and 8 years from the end. This all saves a few D-Checks.
You need to keep a spreadsheet containing details of each aircraft so you can keep track of where you're up to. When I go on holiday and don't take a laptop, things SERIOUSLY fall to pieces!