That's what Nintendo and game freak planned for dragon types weaknesses to be there will be no more weaknesses until they make up more Pokemon types which is highly unlikely.
Ice, Fairy and Dragon-type moves.
Flygon is a Dragon and Ground type pokemon. It's weaknesses are Ice type moves and Dragon type moves.
Dragon-type Pokémon take double damage from Ice Type attacks, Dragon Type attacks, and, starting in Pokemon X and Pokemon Y, Fairy Type attacks, unless their secondary typing cancels the other. E.g., Ice has a normal effect on Kingdra since it is Water/Dragon.
Dragon and Ice Types
Dragon type Pokemon are weak against Ice, Dragon, and Fairy type moves.
Dragon Pokemon are weak to ice and dragon type moves, and resistant to electric, fire, grass, and water type moves (By resistant I mean that when those type moves hit a dragon Pokemon, they will only do half the damage that they normally would). (This answer only applies to pure dragon Pokemon. Extra types such as flying/dragon, will have more weaknesses and strengths.)
Like Dragonite, Salamence is a Dragon and Flying type. It's only weaknessess are: Ice type moves Rock type moves Dragon type moves
Ice-type Pokemon are resistant to only Ice-type attacks. In offense, Ice-type Pokemon can do 2x the damage to Grass, Ground, Flying, and Dragon-type Pokemon.
dragon and i think ice
Garchomp is a Ground/Dragon-type Pokemon, so it's weak to Dragon, Ice, and Fairy-type moves.
A Dark Dragon Pokemon takes double damage from Fighting, Ice, Bug and Dragon moves.
it depends on the pokemon.....example:i have a Pikachu its weekness is water,i have a Piplup is weekness is ice.....