The difference between flight and leaps have been thrown around alot in Smallville. Clark's flight ability has been dormant ever since season one when Clark woke up hovering over his bed. After quickly realising what was happening Clark fell and destroyed his bed. After this the flight ability was not seen again until season three's finale "Covenant" where the fake Kara of Krypton came to lure Clark to Jor-El. However in the season two episode "Insurgence" Clark launched himself from the Daily Planet to Luthorcorp Plaza. This display was in my opinion neither flight nor a super leap. Clark simply took a running start and just fell due to gravity. He only made it to Luthorcorp Plaza because he had a large amount of momentum.
The true flight ability was seen for the first time in season four's premier "Crusade" where a brainwashed Kal-El used it to take the stone of fire from Lex from his jet. After Clark regained control he explained that he could not fly. Clark has stated on many occasions that he is scared of hights however the real reason for being grounded could be either his maturity as a Kryptonian or the fact that he still sees himself as a human as explained in season nine's premier "Saviour".
On a few occasions however like in the episodes "Lucy", "Hidden", "Crimson", "Prey", "Hex", "Doomsday", "Warrior", "Charade" and "Lazarus" Clark has defied gravity but not actually flown hence the name "Super Leap".
The difference between a super leap and actually flying is that a super leap is an initial force and the flight ability is a secondary force. So in actual fact flight involves two abilities; 1: The leap to launch off the ground and 2: The force to maintain and change directions once in the air.
Clark has been able to utilise the leap but not actual flight. Some people seem to think he occasionally flies but he has never actually achieved this while conscious like in season ten's "Lazarus". Even in "Supergirl" Clark does not really fly, he sought of does for a moment but then fails. He launches himself and fails to maintain flight once in the air once he realises what he is doing.
Despite the ability being dormant for years it is starting to reveal itself. This is shown in season ten's "Homecoming" where Clark hovers while dancing with Lois not actually aware of what he is doing. Finally after years Clark finally flew in "Collateral" unfortunatly it is debatable whether he can actually fly or not since he did it in a virtual reality and not in the real world.
Considering that the series is about to come to a close Clark will fly sometime over the next five episodes. What do you think regarding the situation surrounding Clark's ability to fly.