How to catch latias in sapphire?

[ayu11]

Sorry but i really cant seem to catch the red bird. I have seen it once and it got away. After that i check the pokedex and see its location, but when i reach there, it ran to another area. I dunno why but it is always ahead of me. How can I catch it? Those who have caught it can really help in here... :( thx...

[ayu11]

Oh ya, btw what is a infinity ticket?

[Mew2Too]

Oh, I see! It's another random location case!

Remember in G/S/C how Entei, Suicune, and Raikou always ran, and you encountered them randomly? (In fact, they ran from you even when you got to other cities.) It must be the same with Latias and Latios.