The second child of Tar-Meneldur and Almarian of Númenor, Ailinel's elder brother was Aldarion, who later became King Tar-Aldarion, and her younger sister was known as Almiel. Ailinel wedded a noble named Orchaldor, a descendant of the House of Hador, and they had a son named Soronto.
Because her brother Tar-Aldarion had only one child - a daughter - he changed the law of succession so that child could become a Ruling Queen. According to some readings of Númenor's complex laws of inheritance, if the law had not changed, Ailinel's son Soronto would have become Tar-Aldarion's heir. If history had been different, then, Ailinel would have been the foremother of the succeeding Kings of Númenor (though sources differ on the technicalities of this point).