100-0 Ganon's favor. Ganondorf ALWAYS wins this matchup.
Ganon dittos, the most epic dittos ever. Because Ganondorf is a bad character, this means that the options he has aren't as gay, meaning that there is better flexibility in these dittos than in basically any other matchup.
You can play either offensively or defensively in this matchup for the most part, although this depends on part analyzing your opponent's strategy. There is pretty good room for mindgames on both ends.
Some things to note...well-timed D-airs stop the classic Flame Choke, Wizkick, and Dash Attack "approaches". Any other well-spaced aerial beats D-air, U-air is most useful due to its range. Spotdodging is actually useful in this matchup due to the commitment Ganondorf has on several attacks like Flame Choke. Ganondorf is also able to Jab out of spotdodge in this matchup effectively, even though I still wouldn't recommend it over shielding.
Most of the KOs in this matchup will be scored through undiminished F-smash, F-air, D-air, or gimps offstage. F-smash in my opinion, is much better as a damage tool than as a KO move. D-air is a great KO move, but mostly that only happens for revenge KOs, but if you're careful, and don't fastfall, you can get some easy spikes with it too. F-air is the best one for direct KOs IMO. Predict your opponent at the ledge, predict an air dodge, or anything they misspace, and you can land it pretty easily. More likely however, you'll be able to gimp your opponent once they go offstage. A well-placed U-air is your best weapon offstage of course.
Flame Choke is a big mindgame in this matchup, but it is still extremely useful. From what I observed, Swoops really likes doing retreating D-air -> Wizkick to cover as many options as possible.
And yeah, I dunno what else to say. Ganon dittos are too good.