I usually play as Cybran, in FA, so this article will be written from that point of view. However, it can be adapted to work with UEF, albeit less effectively. This has worked every time I have tried it, but I only play against AI, so it might have to be adapted for online play. Also, I usually play on Seton's Clutch, and that is where it was developed. However, it would probably also work on most large, 8 player maps. This strategy is worthless on maps where you are very susceptible to land attack, because there is no economy to spare for PDs.
Note from another's editor: PD's are for commanders without a radar, all T1 bombers are capable of annihilating an army of any size, given enough bombers
Get a solid economy up, with at least four mass extractors, four power generators, and one land factory, and then start pumping engineers. Grab as many mass extractors as possible, and then build as many air factories as your economy can support. I would recommend at least 5, and more is better. Then, start building tech 1 bombers as fast as you can. Pile up around 32-35, and then fly them out and attack the closest enemy commander. It might kill him, and it might not, but it will test the defenses. If the base is heavily defended, then pile up about 70 bombers, and tell about ten to attack each clump of anti air turrets, and then to attack the ACU. Bring up the back with a force of about another thirty, and have them target just the ACU. If this fails, then you will have to transition, but there is a good chance you knock out at least one of the enemy. As soon as shield generators go up, then the bombers are useless, and should be abandoned. Remember that land factory? Upgrade it to tech three, assisted by all your engineers and your ACU, and pump out 2 engineers. Have these go to work on a Fatboy or Monkeylord, depending on the faction, assisted by everything your economy can support. Get two of each, and charge the closest base. Kill the commander, and then send what is left over and two more to the next base, and so on. This strategy will need to be adapted to each individual situation, and may or may not work for online play, but I hope you try it and see how it works.