Your flying ointment will be stronger if you use fresh, rather than dried, plants. 
Pour pure olive oil or warm lard or coconut oil over the plants until they are completely covered.

Make sure nothing protrudes. An extra head of fat/oil protects against mold.

If using lard or coconut oil, set your brew in the sun or keep it in a barely-warm oven.

If using olive oil, keep your brew inside, away from the sun. 
Strain out the herbs after six weeks.

To thicken:
add some melted beeswax to the oil; chill the lard or coconut oil.

Roots of Jimson weed (Datura stramonium)*
Roots of monkshood (Aconite napellus)*
Leaves or seeds from second year plants of henbane (Hyoscyamus niger)*
Green berries of black nightshade/garden huckleberry (Solanum nigrum)
Green berries of bittersweet nightshade (Solanum dulce-mare)
Flowers (if available, but leaves will work) of marijuana (Cannabis sativa)
Seeds and leaves of Indian tobacco (Lobelia inflata)
Flowers of mugwort/cronewort (Artemisia vulgaris)
Leaves and flowers of wormwood (Artemisia absinthemum)
Berries of poke (Phytolacca americana )*
Leaves or seeds of garden rue (Ruta graveolens)*
Flowers of mullein (Verbascum thapsus)
Fresh catnip in flower (Nepeta cataria)

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* These plants are considered highly poisonous. Some people have skin reactions to touching the fresh plants.
Handle even dried plants with care.