The husband of a former Delta Air Lines employee who admitted using her security credentials to smuggle drug money pleaded guilty yesterday to his role in a meth trafficking ring that operated between California and Hawaii. Falefia Fuamatu entered his plea to a conspiracy charge involving distribution and possession of methamphetamine.  The indictment says he flew from Honolulu to Los Angeles at least twice, delivering nearly $1 million in drug money.  His wife, Sifatutupu Fuamatu pleaded guilty last week.  Sentencing for Falefia is set for December 16.