A resposta para a esta pergunta identifies the "pods" as tip tanks.
Por quê do manufacturers sometimes use tip tanks rather than wing tanks? Or is it only when the wing isn't large enough to hold the desired fuel quantity? It seems like filling the wing with fuel first would be more efficient due to less drag.
Tip tanks are only used when the wing volume is not sufficient to carry the needed fuel. They can mostly be found on the early jets which had thin wings for a higher Mach number of drag rise onset and very thirsty engines. They offer two advantages over conventional external tanks:
Later designs used the area rule to shape the tip tanks, so they could help to reduce wave drag a bit, especially on designs which predated the knowledge of efficient transsonic shaping.
On fighter aircraft, tip tanks should be jettisoned with the start of air combat because their high roll inertia contribution puts the aircraft at a clear disadvantage.
The XF-104, the prototype of the Lockheed Starfighter. Where else would it allow to store all the fuel?
For small planes, putting fuel in tip tanks lets you add extra capacity without having to re-engineer the fuel cells inside the wing or the shape of the wing itself. It also lets you offer the plane for sale with or without the tip tanks so your customers can tailor the available tankage to best match their intended use model for the plane.
It also means you can add tankage without having to put fuel in a fuselage tank near the passenger compartment, thereby reducing fire hazards in a crash and improving things like load distribution issues on the main spar.