Judgerussellford, according to Revelation chronology the transfiguration would be a future occurrence when Jesus comes in kingly power. The disciples thought they were Moses and Elijah but Jesus did not confirm their assumption. Because of not being named and being a part of the 144000, it is more realistic to believe that they would display the spirit of Moses and Elijah. Malachi prophesied that Elijah would come. Jesus named John the Baptist as being this Elijah. But he did not say that an Elijah figure would not come again.
Dropoffyourkeylee, that is similar to Seventh Day Adventist teaching. They view the two witnesses as representing the Law (Moses) and the Prophets (Elijah).