The standard in aviation is same as Nautical. That is Degrees and Minutes, and if a position needs to be depicted more precisely than that, they don't use Seconds (60 in a minute) they use tenths of minutes.
So you will see "45o 30'N" for 45 degrees, 30 minutes, but for a more detailed locator, they just add a decimal to the minutes value, instead of seconds. Thus it becomes something like "45o 30.6'N" for 45 degrees, 30 minutes and 6 tenths of a minute. The grid sub unit marks on aviation charts are in tenths of a minute as well.
In our institution, we operate a research helicopter based on the Eurocopter EC135 (now renamed to Airbus H135), the ACT/FHS.
As we develop control algorithm for this machine we use two formats:
Due to the digital output of our custom Inertial Navigation System, we use the decimal representation of the GPS coordinates (like 52.51625 °N, 13.37767 °E). This is the most convenient format, as we can use it digitally.
Often, for local navigation, we translate these coordinates to a local NED frame, which we then can use for a lot of local navigation algorithms. In this frame we can say that we are for example 500 m North, 200 m South and 300 m up from a given reference point. This is a lot easier to use, however if you are farther away then 30km from your reference point, the local approximation really starts to show.