If two individuals have a certain phenotype, does that mean they must have the same genotype?

No.As we know that phenotype depends on physical appearance whereas genotype is genetical materials. So person having same phenotype doesn't mean they have same genotype.

i believe you meant to say air rather than hair so the answer is below ")

the dead sea, the lowest place on earth at 430 metres (1,410 ft) below sea level, has a correspondingly high typical atmospheric pressure of 1065 hpa.