Why can't I fly to Route 120?

Question

In OR/AS, I noticed that you can fly to Routes. So, I tried to fly to Route 120 (the route east of Fortree), and it wouldn't work! I've flown to every Route available to me so far, except 120 because it won't work! Inconvenient much, especially when my Secret Base is there. Why is this happening, and how can I fix?

Comments

Some just don't work, mainly the routes just water fills, but some still won't work, and have you walked there? Because if not, do so and you should be able to fly there.

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You can fly to routes?

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I walked there. Repeatedly. Heck, my Secret Base is on route 120.

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Yes you can. Try it on ORAS.

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Edited to comment because it doesn't really answer the question.

Answer 1

Well, I could and I'm at the Pokemon League.

My only guess is that you haven't made it to Route 121 or Lilycove.
You are unable to fly to routes if you haven't made it to the town (or route, possibly, in this case) after it. This is proven on Route 121, coincidentally the route after this one; there is a woman that states you have to make it to Lilycove in order to fly to Route 121.

If you have made it to Route 121/Lilycove, I guess its a glitch. Sorry...

Hope I helped. :)
Source: Experience