Standby tickets are available with ourselves and all major airlines. Unfortunately, it's done by emailing a scanned copy of a form to our staff travel department who then issue you with a ticket (it used to be a paper ticket in the post up until a couple of months ago!). ID90/other electronic means of booking standby tickets is apparently coming. But it's been "coming soon" for 10+ years. I think it's now actively being looked into. After 1 year service we are given online access to BA staff travel (it's available from date of joining but via the form described above until you get online login). This can only be used to book standby tickets.
Confirmed seats AKA "late seats" are also available but are only confirmed 3 days in advance. Generally, you'd give staff travel a few destinations in order of preference and they work down the list. Nice for spontaneous last minute trips or taking the other half on a week trip to Costa Rica. Standby and late seats are very cheap.
Being a 'holiday airline' we are issued with concessions every year to be used towards a package holiday. The amount depends on years of service. I think year 1 is £500 or £750 and is capped at something like £1750 a year. Don't quote me on the numbers. These are confirmed seats/airport transfer/hotel rooms etc, can be booked well in advance and are great for taking the family away.