FlyingZiggy, I have no inside knowledge about AirBaltic,
but a general answer to your question.
One way of financing your company is via bonds. A bond is a debt with a fixed interest rate and a fixed payback date (of the debt).
If you make a bond with a long runtime (=payback date long in the future) and during times your business is very stable (giving you a low interest rate), it can happen that your business outlook deteriorates during the runtime of the bond and once your bond is up for renewal (= you need to pay back the debt and find someone to lend you the same amount of money again, (if you do not have the cash to just pay the debt off)) then it could be that due to your now bad business outlook no-one wants to lend you money again or just for very high interest rates.
This can bankrupt you immediately if you do not get any new bond or it can bankrupt you over time due to the now higher interest rate.(which is a cost).