1. Cosmetic composition comprising a mixture of: - particles of a hydrophobic silica airgel having a specific surface area per unit mass (S) in the range from 500 to 1500 m / g and a size, expressed as the volume mean diameter (D [0,5] ) in the range from 1 to 1500 microns, and- at least one first linear silicone oil having a viscosity of more than 50 mm / s, and at least the second and third linear silicone oils, each of which has a viscosity of less than or equal to 50 mm / c.2. A composition according to claim 1, characterized in that the first linear silicone oil has a viscosity of greater than or equal to 100 mm / s, even better greater than or equal to 200 mm / s, even better greater than or equal to 300 mm / s, and which can reach 1000 mm / p.3. A composition according to claim 1, characterized in that the second and third linear silicone oils have a viscosity of less than or equal to 30 mm / s, more preferably less than or equal to 20 mm / s, more preferably less than or equal to 15 mm / p.4. A composition according to claim 1, characterized in that the first linear silicone oil is present in a mixture of linear silicone oils in an amount less than or equal to 20% by weight. relative to the total weight of the mixture of linear silicone oils, preferably less than or equal to 10 wt.%, more preferably less than or equal to 5% mass.5. A composition according to claim 1, characterized in that each of the second and third linear silicone oils are present in the mixture of linear silicone oils in an amount greater than or equal to 40% by weight. relative to the total weight of the mixture of linear silicone oils, preferably more than or equal to 45% mass.6. A composition according to claim 1, characterized in that it comprises: - at least one first linear silicone oil, n
