I don't know of any airlines that stipulate you can be any less tall than the standard height requirement.
Do you always get your height checked? -- At the recent recruitment day I went to [DJ] they didn't make mention of any height [even though we all know we must be of a certain height as stated on their applications] I assume they check this for sure if you're lucky enough to get to the medical stage. I don't know what would happen if you got that far and were found to be "half a centimetre under", whether that automatically means you're unsuccessful or not!
A half a centimetre seems so tiny a gap. I really hope this somehow doesn't prevent you from achieving your goals!!