getFleetsFighterPowerText = (
            viewFleet = PlayerManager.fleets[0],
            escortFleet = PlayerManager.fleets[1],
            isCombined = false) => {
        var mainFleet = viewFleet;
        if(isCombined) { // force to 1st fleet if combined
            mainFleet = viewFleet = PlayerManager.fleets[0];
        }
        switch(ConfigManager.air_formula) {
            case 2:
                return "\u2248" + (
                    isCombined && ConfigManager.air_combined ?
                    mainFleet.fighterVeteran() + escortFleet.fighterVeteran() :
                    viewFleet.fighterVeteran());
            case 3:
                const mainBounds = mainFleet.fighterBounds();
                const escortBounds = escortFleet.fighterBounds();
                return  (isCombined && ConfigManager.air_combined ?
                        mainBounds[0] + escortBounds[0] : mainBounds[0])
                        + "~" +
                        (isCombined && ConfigManager.air_combined ?
                        mainBounds[1] + escortBounds[1] : mainBounds[1]);
            default:
                return isCombined && ConfigManager.air_combined ?
                    mainFleet.fighterPower() + escortFleet.fighterPower() :
                    viewFleet.fighterPower();
        }
    }
Get fighter power text from 1 or more fleet(s), especially served for Combined Fleet.

@param {Object} viewFleet - Fleet object currently being viewed, default 1st fleet.
@param {Object} escortFleet - Fleet object of escort for Combined Fleet, default 2nd fleet.
@param {boolean} isCombined - if current view is really Combined Fleet view, default false.
@return {string} fighter power text, formation according config: `air_formula`.
@see Fleet.fighterPowerText similar function only served for Fleet object.
@see Fleet.fighterVeteran
@see Fleet.fighterBounds
@see Fleet.fighterPower