There is no single, universal technique for making random food "fluffy". And you may have to live with significant changes in the recipe and in the final results if you try it.
Classically, you have three types of foams. One is fat-based, the other is protein-based, the third depends on sudden gas production/dissolving.
The fat-based foam is only possible in liquids which are an emulsion of fat in water, and only functions within a certain range of fat/water, a favorable temperature range, and a proper size of the fat globules. This is what whipped cream is. Besides cream, you can whip that way a few other things such as ganache or mayonnaise (although mayonnaise is a bit more complicated, since it also has protein). It is almost impossible to make at home an emulsion which will behave that way, you may succeed with lecithine and very good equipment (a lab-style homogenizer will be preferable over blenders and other kitchen staples), and you will be very limited in the ingredients you use.
The protein-based foam happens when proteins link. This is also possible with only a few ingredients in the kitchen, most notably egg whites, aquafaba, and, under the right conditions, milk (that's what cappuchino wands do). It is even more finicky than fat-based foam.
The third one is the (more-or-less sudden) release of gas. This is e.g. how beer foam happens. They are always very short-lived for liquids, although in principle a sponge cake and similar baked goods are a batter that has been set into this bubbled-up state by baking.
None of the three types above are applicable to a random liquid or sauce. They all require that you start with a known ingredient that creates foams, and whip it under the proper conditions, with the least amount of additions.
A fourth, more modern way, is to try forcing a gas into the liquid from outside. This is how soda stream works, or whipped cream siphons. This can in principle work with a wide variety of liquids, but you have to do quite some food engineering before the resulting texture is acceptable. Most liquids won't hold the foam as-is, if they whip at all, so you have to add a binding agent.
So, if you want to really make a random sauce into a foam, the way to do it will be to purchase a siphon (don't forget to invest into enough charging cartridges, you will need a lot for your experimentation) and a variety of gums and other binding agents. Then you will have to experiment to determine the proper binding agent (and the proper amount of it) for your sauce. Since you probably don't want to run many hundreds of experiments per sauce, it is advisable that you also get the proper literature on the functioning of binders, and gain some hands-on experience by first following existing, optimized recipes for foams. After that, you can start designing your own recipes, and will probably get away with a dozen or two of experimental runs per sauce, depending on your level of experience and how exact your expectations of the outcome are.