Yep, you can have a one sided holiday, NATS are masters of thier scheme for their staff. You can have a holiday both ways in fact. Cannot think why the employees would be given a payment holiday in lieu of a pay rise.
As Orson said, companies can lawfully stop thier contributions into a scheme and I believe they can make up later any shortfall as agreed by actuaries and trustees, although I stand corrected.
If our new esteemed leaders are resorting to this, the plight of our company and our staff could be considered to be VERY serious.
Do not read too much into the holiday, but read that NATS has a (Huge) financial problem, either now, or looming! That worries me!