In pokemon Heartgold
you cant. You can only catch it in Pokemon emerald, but, you cant catch latias in emerald.
latias
you dont catch it.you shoud have an action replay to catch it or an other pokemon game to sent it from there to there.i prefer the pokemon ss or hg where u can catch almost all legendaries
You can only get Latias in Diamond by importing it from PalPark.
You can find latias on every route in hoenn.
Yes you can. later in the game Latias (or latios depending on which game you have) is attainable. Like mesprit in Pokemon diamond and pearl and like mesprit, latias and latios tend to flee.
Yes.
Yes, Pokemon Sapphire version is the version in which you can catch Latias. You can only find it once you have beaten the Pokemon League, then there is a report of a legendary red flying Pokemon in Hoenn. Latias appears randomly.
You can't catch it anyway, you can trade it from another Ruby Sapphire or Emerald game.
You can't
It is possible, but you can't catch them both on 1 Pokemon game. If you have Pokemon Emerald, Ruby and or Sapphire. Then you can get them both. For example: Someone trade Latios and you have Latias, trade an another Pokemon for Latios and you have them both.
For Pokemon ruby you can catch the three regis, rayquaza, groudon, and latios/latias. In sapphire you can catch the three regis, rayquaza, kyogre, and latios/latias. However, in emerald you can catch kyogre, groudon, rayquaza, the three regis, and latios/latias.