1) Who exactly are entitled to get ID90 tickets? Only airline personnel or travel agents etc. as well?
stands for Industry Discount. Travel agents are sometimes eligible to receive ID
tickets.. i.e. ID90/75/50 on certain carriers. Airline employees are also eligible to receive ID
tickets on other IATA airlines, the discount amount is up to the carrier. Usually it is ID75 or ID90. Handling agents, also receive these tickets on some airlines they handle. I work for a handling agent so I can testify to that.
2) Is it 100% comp. or a discounted rate?
ID90 is 90% percent off so if full coach fare is $1000..the cost of the pass will be $100. Ditto for ID75 and ID50. Many carriers also issue service charge passes where the employee pays a flat $25 or $50 for each 1 way segment. It all depends what is negotiated between carriers.
3) Can you as someone who works for an airline purchase an ID90 for someone else who doesn't work in the airlines?
As SWAFA30 said..... but note the following..
Take US AIrways for example, their staff, domestic partners, dependents, including parents receive ID00 tickets (they just pay applicable taxes). They however are allowed to give out 8 buddy passes per year to whomever they wish. These buddy passes are ID90's for use on US Airways only.
4) Are ID90 tickets available on all carriers/routes, regardless of which airline you may work for?
as SWAFA30 said....
5) How do you book these tickets, and is it all flying standby? What are the other conditions attached to these tickets?
ID90's are booked usually by the carrier who the staff works for. Some carriers would have the passenger check with their staff travel desk though. ID90's are all standby tickets and are usually lower priority code, than the staff of the airline who you have the ID90 ticket for. Normal non-rev rules apply...
There is something special about planes....