The major airline I work for monitors sickness in flight crew in 4 stages. Every time you are off ill, it "counts" towards your running total for a given period. After each period off your need a "return to work" interview and after two such episodes you are set a "target" of not being ill for a given period. Failure to comply moves you up a stage until investigations are made to find the underlying cause of continued absence. If this is medical then treatment is arranged, family problems are also taken into account and help offered where appropriate.
If none of the above applies - Flying Fiona
then a written warning is issued and failure to comply leads to dismissal.
This has lead to a dramatic fall in days off and our average is barely above the national average for ground based jobs.
Oh and our cabin crew have refused to join in - wonder why?