So, the training rules PG.334.
Seem quite detailed.
Simple skills are easy to put up, roll on it at least once or get a weeks training and it can go up.
Advanced skills require training, a months worth from a trainer with better skills...
First problem here is that the PC's may in fact be the most skilled pilots on planet... This effectively locks out advancement.
The system does not seem to account for field learning...
What about learning more than one skill at a time during training?
Training skill PG.156
Using a skill to gain XP, sounds like a downtime application of a skill to me. I think I will treat it this way.
OK, time for two house rules. Or are they more house additions...
First - the character sheet needs a tick box for skill has been used and can be advanced. For simple skill just tick it as a reminder.
1) learning advanced skills by doing.
First step, the character spends the advancement points to advance the skill then ticks the advance box to signify the skill is in training.
This does not actually advance the skill.
Next the skill advances when one of two conditions are met. The first is that the character makes a test on the skill obtaining a MOS equal to the level the skill is advancing too. The second is that a number of months pass in equal to the new rank of the skill.
This option does not alow you to purchase an advanced skill at rank +0. Training is still required for that.
2) learning more than one skill at a time during training.
We do it in real life so why not...
Training time can be applied to a number of skills equal to the characters INT.
Some notes for my thinking, here is the incremental cost of skills -
+0 - +20
+1 - +10
+2 - +20
+3 - +30
+4 - +40
+5 - +50
+6 - +60
+7 - +70
+8 - +80
+9 - +90
+10 - +100
Finally, I forgot to add to the last post. Character creation under priority is balanced between point buy. Nicoli almost scared me

a character with skills C buys 6 skills at +4 and one at +3 - this adds up to 800, as does 10 skills at +3 and 40 skills at +0. Anything else gives a refund. Took me ages to work that one out...