Drake and Josh's stealing of Tony Hawk's car could not have happened because the valets already parked it.
When Drake says that Josh and him have to go get their haircuts, Drake messes up Josh's hair by sticking it up. But then when they get outside to Tony Hawks Viper, Josh's hair is all flat again
All the airplanes shown change make, model, and paint job multiple times.
When Drake and Josh take Megan to the airport, they are seen leading her onto the plane in the terminal. However, they wouldn't be able to get past security if they didn't have tickets for the flight, which they have to buy later on after they are in the terminal.
Being that she is an 11 year old girl, Megan would not be permitted to book a hotel room alone.
When Drake and Josh are in the San Diego airport after Meagan departs, a television news program brakes to an on-the-scene report. The reporter says he is standing in front of The Treasury Building, yet is clearly standing in front of The Capitol Building.
When Megan arrives at her Suite at the hotel, the doors to the room have automatic closers. But when Megan and the Bellmen walk in the doors stay open.
When Drake and Josh are driving Megan to the airport, the picture car they are in has no seat belts.
The pilot's voice is the same on both flights. Both of them were in the air while they were flying to their destination. It's also the voice of a lot of radio shows and TV news reports. The reporter that Josh is looking at on the TV at the airport appears to have also the same voice.
When Drake swerves out the way to avoid an oncoming truck, there is no truck visible out the window of the car afterward.
The woman at the counter in the airport in San Diego would certainly have made an effort to get Megan off the plane, considering it hadn't left yet. Also Drake and Josh would not have been able to fly to LA without several forms of ID.
The entire plot device of which Josh's story is built around is contradicted by the rest of the series. Why does he feel nothing exciting has happened to him? The other seasons have countless adventurous, exciting things happening to the brothers.
When Josh meets Alan Krim in the bathroom, Krim accepts Josh's request of having Drake on TRL and Krim told Josh to have Drake at Sunset Studio in Hollywood at 4 o'clock. Later on, when locked up in the warehouse, Drake and Josh wake up at 2 in the morning, and Drake said that he had to be at Sunset Studio in 15 hours, which then would be 5 o'clock instead of 4 o'clock.