If you can consider a bomber a fightercraft, it's the UEB Durga, armed with tri-Gattler banks equating to twelve Gattler gunpoints, two or so anti-ship missiles, six or so slammers and a hundred or so random forced heatseeking dogfight missile.
If not, the UEF Uriel for it's Archer and overall nice-looking. And when you can nail fighters with Archer-kun by chance or skill.
For the GTVA, it's definitely the GTB Boanerges or the GTF Myrmidon.
Because the GTF Ares has an insanely awesome EN recharge enough to fire dual Kaysers/Maxims for quite some time and do interception, good shielding, enough hull to take quite a few AAFs and still be able to play ramming games. The best of all, that 80/100 bank with 11 + 13 Trebuchets to maul people at long range. I would never fly any GTVA fighter that is not the Ares or Perseus or Pegasus or the Loki unless the mission forces me to.