First: Errors Related to Ihram:

Some pilgrims bypass the designated Station of ihram on their route without either being in Ihram or entering into ihram there, proceeding until they reach Jeddah or some other place within the precincts of the Stations, at which they enter into ihram.  This is against the command of Allah’s Messenger (peace be on him), which stipulates that every pilgrim should enter into ihram at the Station of ihram which lies on his route.  

If this happens to someone, he must either go back to the Station of  ihram lying on his route and there enter into ihram, or he must make expiation by sacrificing a sheep in Makkah and feeding all its meat to the poor.

This applies to all pilgrims regardless of whether one passes the Station of ihram by air, by sea or by land.  

If one did not pass through one of the five designated Station of ihram he should enter into ihram at a point which is nearest to the Station of ihram on his route.