In the event someone in line decides that they don't like what they see and requests a change of heading, having altitude separation works nicely to give them what they need without conflicting with another aircraft.
In the Tower or Approach control, working two airplanes or 10, the tools were (in no particular order): preplan, use course divergence when altitude separation isn't available, prioritize your transmissions and manage the frequency.
I said we would remain at 500 feet until feet dry, thus maintaining altitude separation
The second phase of the flight along airway UZ6, according to the flight plan, implied a change in altitude for a reason, since UZ6 is a two-way airway where altitude separation
This includes critical altitude information for compliance to new mandatory reduced altitude separation
standards (RVSM, Reduced Vertical Separation Minimum), airspeed and altitude as well as engine and fuel data measurements.
The need for altitude separation
is what precludes controllers from just saying, "Deviations approved.
The squadron had grown comfortable with the 2,000-foot altitude separation
between Baja and the tanker with his dozen chicks in tow; I hadn't yet reached that comfort level.
To protect airspace around each flight, altitude separation
is used in case an aircraft makes a surprise deviation around a cell.
Lead should have detached Dash-2 and -3, providing altitude separation
at the rendezvous point.
Telling ATC you're unable to climb or descend more than 500 feet per minute is an FYI so the controller doesn't rely on a 500 fpm climb or descent rate when applying altitude separation
with another airplane.
From the TCAS, we determined that the lead Hornet would fly right under our airplane, with little or no altitude separation, if we both maintained our current flight paths.
The aircraft commander applied power and leveled off,verifying that I had the Hornet in sight and that we had altitude separation.